Nadia Soulmi

Ana Gabriela Porras Gutierrez

Cecile Rizzi

Juliette Sirieix-Plénet

Laurent Gaillon

Henri Groult

Anne-Laure Rollet

Evrim Umut

Danuta Kruk

Mathieu Duttine

Cécile Rizzi

Anne-Laure Rollet

Olaf J Borkiewicz

Oleg I Lebedev

Damien Dambournet
email: damien.dambournet@sorbonne-universite.fr

C Rizzi

A-L Rollet

A-L Rollet

Sn-based alloys synthesized in an ionic liquid at room temperature : Cu6Sn5 as a case study

Keywords: Sn-Cu alloys, NMR relaxometry, cyclic voltammetry, ionic liquids nanoparticles, surface interactions, lithium-ion batteries

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Introduction

Sn-based alloys are an interesting class of materials for applications spanning from catalysis to electrochemical energy storage. Alloying serves as a mean to tune the solid electronic properties [1] and can provide enhanced electrochemical performances in lithium cells owing to the formation of an inert matrix [2] . The precise control of the atomic structure of alloys appears, however, largely dependent on the synthesis method employed. Although ionic liquids are considered as suitable solvents to prepare unusual materials, the synthesis of binary alloys is more challenging. The resulting compound may not be alloys but core-shell like nanoparticles, fused clusters, or simply a mixture of the monometallic nanoparticles. [3] This diversity of results is due to the numerous contributing factors that are the nature of the solvent, its compatibility with the metallic precursors, the reaction kinetics and metal surface interactions with the solvent.

Literature data dealing with the synthesis of Sn-based alloys in ionic liquid solvent mostly relied on the decomposition of metallic precursors. For example, Wegner et al reported the synthesis of ruthenium and tin metallic alloys using 1-Ethyl-3methylimidazolium tetrafluoroborate [BMIm + ][BF4 -], leading to the formation of Ru2Sn alloys and a mixture of a Ru3Sn7 and α-Sn phase. [4] Dietrich et al used PtCl2, SnCl2 or Sn(acac)2 as metallic precursors, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide as the solvent and triethylborohydride as the reducing agent. Pt-Sn alloy nanoparticles were obtained without being able to strictly define the synthetized phase. According to x-ray diffraction analysis, the crystalline phase obtained were indexed with cubic metallic Pt, with diffraction peaks displaced to smaller Bragg angles, indicating the incorporation of Sn into the Pt lattice, and the possible formation of randomly alloyed nanoparticles. In addition, small SnO2 nanoparticles in close contact with alloyed nanoparticles were observed by HRTEM. [5] This illustrates the difficulty to control the composition of the alloyed phase.

To control the chemical composition of Sn-based alloys, we proposed to use metallic precursors based on TFSI -counter ions dissolved in an [EMIm + ][TFSI -] ionic liquid. The use of common anion for both metallic precursors and the ionic liquid was shown to be an effective approach to (i) increase the solubility of cations in ILs, [6,7] especially as compared to conventionally used halide salts, [8] (ii) prevent impurities related to Cl -anions [7] and (iii) enable the successful synthesis of nanosized metals [6,7,9,10] . We selected the tin-copper system and particularly the Cu6Sn5 chemical composition for its possible use as an anode for lithium-ion batteries. We compared the synthesis employing TFSI -based precursors with conventionally used chloride salts.

Results and Discussion

Synthesis of metallic Sn. The precipitation of metallic Sn synthetized using NaBH4 as the reducing agent in [EMIm + ][TFSI -] ionic liquid was investigated using two salts that are Sn(TFSI)2 and SnCl2. In both cases, the addition of the salt and the reducing agent dissolved in [EMIm + ][TFSI -] results in the formation of a black precipitate. Figure 1a gathers the X-ray diffraction powder pattern of both samples recovered after the synthesis. As previously reported, [11] the use of SnCl2 led to the formation of a phase mixture consisting in -Sn and NaCl as an impurity. The use of Sn(TFSI)2 enabled to prepare single phase of -Sn without any traces of impurity.

We further compared the particle size and polydispersity of the two samples. Sn(TFSI)2 precursor led to an average particle size 15 nm (Figure S1) which is larger than that observed for SnCl2 (7 nm). This increase of the particle size is accompanied by an increase of the size polydispersity going from 29 to 35%. Such differences suggest that the nature of the cationic precursor affects the nucleation/growth mechanism of metallic Sn. This can be tentatively explained by differences in metallic salt solubility. The low solubility of SnCl2 precursor might result in a continuous supply of cations promoting growth of metal particles with a smaller size and a narrower distribution. [12,13] NPs stabilization probed by NMR relaxometry. The chemical reactants used provides a versatile system to investigate the nature of the interactions between the ionic liquid and the surface of the nanoparticles. To do so, we explore the use of 1 H and [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F spin-lattice relaxation experiments performed on a solution containing freshly precipitated -Sn prepared using the TFSI - precursor, in the frequency range of 10 kHz -40 MHz (referring to the 1 H resonance frequency). "Classical" NMR relaxation experiments are performed at a single magnetic field while here, the magnetic field can be varied in a very broad range thanks to the concept of Fast Field Cycling [14,15] , a technique well suited to probe the interactions between a solvent and nanoparticle's surfaces. [16] The great advantage of this method is its ability to probe in a single experiment, molecular and ionic dynamical processes occurring on much different time scales. 20,[19], 24,25 The relaxation dispersion profiles (relaxation rates plotted versus the resonance frequency) reveal specific effects (not observed in "classical" NMR relaxation studies) that can be treated as a fingerprint of the slowing down of ionic dynamics due to interaction with surfaces. Here, we used an original approach as the experiments were performed at the frozen state and exploit the modification of the 14 N nuclear energy levels induced by the presence of metallic nanoparticles. Indeed, the standard approach is to record relaxation dispersion profiles in the liquid state and to model the fluctuations of the dipolar interactionssource of relaxationexperienced by the nuclei. [18], [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] In other words, the goal in liquid is to model the dynamics of the molecule: rotation, diffusion in the bulk, diffusion at the surface of the particles, etc. [18,[START_REF] Martini | [END_REF][22][23][24][25] In the present situation, it can be tricky to distinguish between the case of the cation (or anion) diffusing on the surface of the raw nanoparticles of diameter D and the case of nanoparticles covered by a layer of anion (or cation) leading to a diameter of D+d (d being approximately 20 times smaller than D). With [EMIm + ][TFSI -], the presence of 14 N in both the anion and the cation can be a source of relaxation enhancement at specific frequencies provided that the dynamic is slow. This effects is referred as Quadrupole Relaxation Enhancement (QRE). 21,[29], [33][34][35] The 1 H ( 19 F) spinlattice relaxation originates from several relaxation pathways between the 1 H ( 19 F) nuclei and other NMR active nuclei in the neighborhood, especially 14 N. As the spin quantum number of 14 N nuclei is larger than ½ (it is 1), the nuclei experience two kinds of interactions: Zeeman interaction and quadrupole coupling, i.e., a coupling with the electric field gradient tensor at its position. For slow dynamics, the energy level structure of 14 N is determined by a superposition of its Zeeman and quadrupole interactions. When the 1 H resonance frequency (the transition frequency between the 1 H energy levels) matches one of the 14 N transition frequencies, the 1 H polarization can be taken over by 14 N, as a result of the mutual magnetic dipole-dipole coupling between the participating nuclei, leading to a frequency-specific enhancement of the 1 H spin-lattice relaxation rate referred to as QRE; the 1 H spin-lattice relaxation maxima are called quadrupole peaks. The positions of the quadrupole peaks depend on the quadrupole parameters which are determined by the electric field gradient tensor at the 14 N position and appear when (as already pointed out) the dynamic is sufficiently slow. [15,[26][27][28] For 14 N there are three quadrupole peaks at the frequencies of 3 4

⁄ a Q (1- 3 ⁄ ) , 3 4 ⁄ a Q (1+  3 ⁄ ) and 𝑎 𝑄 ( 2 ⁄ )
where 𝑎 𝑄 is the quadrupolar coupling constant of 14 N, and  the asymmetry parameter of the electric field gradient at the position of the 14 N nucleus. The positions of the quadrupole peaks can be treated as markers of the 14 N chemical environment as 𝑎 𝑄 and  values are sensitive to the electric field gradient. where motions are sufficiently slow to allow QRE peaks existence. At least six clear peaks (some may be overlapped) on 1 H profile and four peaks on [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F profile are observable. The mechanism of the 1 H and [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F NMR relaxation is the dipole-dipole interaction that decreases as r -3 , r being the distance between the two dipoles, i.e., 1 H (or 19 F) -14 N distance for the QRE peaks. To identify the origin of the QRE peaks, we used the crystalline structure of the solid [EMIm + ][TFSI -] solved by Choudhury et al [30] , and listed the different inter-atomic distances between 14 N and 1 H/ [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F close neighbors (Table S1). On one hand, it appears that all the 14 N carried by both the cation and the anion, are close to 1 H leading to seven observable QRE peaks. On the other hand, 14 N are far from [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F except for the 14 N carried by the anion [30] leading to a lower number of QRE peaks in the [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F NMR relaxation profile. Furthermore, by comparing both profiles, peaks II and III seems to be related to the 14 N carried by the anion.

Similar experiment was then conducted on a [EMIm + ][TFSI -] solution of -Sn freshly prepared using TFSI -precursor. First, this result confirms that the chemical nature of the nanoparticles -and not the possible chemical bonding with the surface -is responsible of the strong modification of 14 N properties. Second, it confirms that the nanoparticles are not oxidized in the ionic liquid. Synthesis of Cu-Sn alloys. The synthesis of Cu-Sn alloy of nominal composition Cu6Sn5 was first attempted using chloride precursors (see experimental section). The addition of the reducing agent led to the successive formation of a brownish precipitate followed by a black coloration (Figure S3). After powder recovery, XRD analysis (Figure 3) revealed the formation of a phase mixture of cubic metallic Cu and -Sn as well as NaCl as an impurity. The successive formation of monometallic nanoparticles, without the formation of Sn-Cu alloys, might be due to a concomitant effect of the low solubility of chloride precursors and standard potentials gap between Cu 2+ /Cu (+0.34 V vs. SHE) and Sn 2+ /Sn (-0.13 V vs. SHE). starting from the open circuit potential (EOCP) toward cathodic and reversed anodic sides. Concerning the solution of Sn 2+ , we observed a cathodic peak at -0.17 V vs. Sn 2+ /Sn previously assigned to the reduction of Sn 2+ to Sn 0 and a re-oxydation occurring at +0.10 V. [7] In the case of a 25 mM Cu(TFSI)2 in [EMIm + ][TFSI -], the voltammograms stabilized after several cycles (Figure S4) indicating that side reactions occurred. Thereafter, the CV showed a reduction peak at -0.02 V vs. Sn 2+ /Sn, followed by an oxidation occurring at +0.53 V. Such a cathodic peak value cannot be assigned based on standard potential due to the contribution of the solvation energy of copper ions in [EMIm + ][TFSI -] solvent. [31] Subsequently, we performed CVs on solutions of 25 mM of Sn(TFSI)2 where we introduced copper with different Sn:Cu molar stoichiometries of 1.0:0.1, 1.0:0.5 and 1.0:1.2 (Figure 4b). For Sn:Cu of 1.0:0.1, the CV present a cathodic peak at -0.15 V assigned to Sn 2+  Sn 0 and a small peak at -0.6V which might be related to Sn-Cu alloy. The anodic scan features a first intense oxidation peak at 0.02V assigned to the oxidation of Sn 0 and a small peak at 0.38V tentatively assigned to the oxidation of Sn-Cu alloy. Upon increasing the copper concentration, we did not observed cathodic peaks characteristic of the reduction of Sn 2+ or Cu 2+ . For Sn:Cu of 1.0:0.5, a cathodic peak is observed at -0.39V along with a broad shoulder centered at -0.77V. These two features can be assigned to the formation of Sn-Cu alloys with different Sn:Cu stoichiometries. In the anodic reverse scan, we observed three peaks at 0, 0.25 and 0.41V, assigned to the oxidation of Sn and two types of Sn-Cu alloys, respectively. For Sn:Cu of 1.0:1.2 that is the targeted nominal composition of Cu6Sn5, the cathodic scan displayed two broad peaks at around +0.0 and -0.6V. The anodic scan showed the absence of the peak related to Sn at 0.0V and a broad peak at +0.54V related to the formation of different Cu-Sn alloys. Cyclic voltammetry revealed that the electrochemical responses of a solution of copper and tin in [EMIm + ][TFSI -] depends on the Cu-Sn stoichiometry. In such a system, the measured redox potential is related to the Gibbs energy of the Sn-Cu alloy. The richness of the Sn-Cu phase diagram is reflected by the numerous peaks observed by CV. This demonstrates that the use of TFSI - precursor is a suitable approach for the control synthesis of alloys.

It should be noted that attempts to measure CVs using chloride precursors failed which can be due to the low solubility of the salt. In agreement with cyclic voltammetry measurements, the use of TFSI-based precursors resulted in a rapid and homogeneous precipitation upon reaction with NaBH4 (Figure S3). The x-ray diffraction pattern measured on the recovered powder (Figure 5) revealed the formation of Cu-Sn based alloy without any traces of monometallic phases. TEM micrographs (Figure S5) showed the formation of nanoparticles with an average size of 17 nm and a large dispersity of 30 %. For the targeted composition Cu6Sn5, two types of polymorphs can be formed and are denoted  and '-Cu6Sn5. According to the binary diagram, '-Cu6Sn5 corresponds to the low-temperature phase. [32] This structure was previously solved by Larsson et al, [33] who described it in a monoclinic system (space group C2/c) presenting a NiAs-Ni2In superstructure. The high temperature modification -Cu6Sn5 crystallizes in a hexagonal system (space group P63/mmc) and presents a NiAstype structure. [34] Attempts to index the XRD pattern did not allow to distinct between the two  and '-Cu6Sn5 polymorphs because of overlapping and broadness of the peaks. To study the atomic structure of the Cu-Sn alloy prepared using TFSI -based precursors, we used the pair distribution function, G(r), particularly suited to investigate nanostructured/disordered materials. [35] The PDF gives the interatomic distance distribution of finding atom separated from the distance r. [START_REF] Egami | Underneath the Bragg Peaks: Structural Analysis of Complex Materials[END_REF] At the short interatomic distance, we noted the presence of a small peak at around 1.91 Å characteristic of Sn-O bonds indicating the presence of oxides. Attempts to refine the PDF data were performed in the rrange of 2.1-50 Å based on structural models of  and '-Cu6Sn5 polymorphs. The quality of the refinement was quantified by the reliability factor weighted R-value, denoted Rw. The use of -Cu6Sn5 as structural model fairly reproduced the PDF data with an Rw value of 29.5% (Figure S6). Structural model based on '-Cu6Sn5 polymorph improved the fit with an Rw value of 24.8% (Figure S6). Finally, a two-phase refinement including both polymorphs as structural models led to a better fit with an Rw value of 20.7% (Figure 6). The refinement of the scale factor, however, indicated that the ' polymorph was the dominant phase, i.e., the mass percents of the ' and  phases were 97 and 3%, respectively. The refinement included a size parameter to account for the finite size effect of the nanoparticles on the PDF with a refined value of 11 nm which agrees with TEM observations. The structural parameters of the dominant ' phase extracted from the PDF refinement are gathered in Table 1 and compared with literature data. Attempts to refine the rate occupancy of Sn atoms improved the fit and revealed the presence of a large content of Sn vacancies. The chemical formula determined from the refinement yielded to Cu6Sn3.31.7 where  represents vacancy. Furthermore, the volume of the cell was slightly larger than the stoichiometric compound suggesting structural distortions which might be due to size effect and/or due to the presence of vacancies. The chemical composition of the phase was further investigated using high-angle annular dark-field (HAADF) imaging with a scanning transmission electron microscope (STEM) coupled with Energy-dispersive X-ray (EDX) spectroscopy. Figure 7a shows the HAADF-STEM image of an isolated particle presenting a coreshell morphology. The observation of lattice fringes (see Figure S7 for detailed view) in the core region suggested that it is crystallized. In contrast, the shell appeared amorphous. EDX measured on this individual particle yielded Cu2Sn1 composition which was close to that found by PDF refinement, i.e., Cu2Sn1.1, therefore supporting the presence of Sn vacancies. EDX elemental mapping showed that Cu atoms were essentially present in the core region of the particle (Figure 7b). Moreover, we noted the presence of oxygen and tin at the shell level suggesting that the amorphous part was related to an oxide layer formed during the washing step [11] . 2) correspond more accurately to the relative proportion of the three associated Sn phases. The refined Mössbauer hyperfine parameters (at 293 K) are consistent with crystalline η'-Cu6Sn5 for the Sn 0 quadrupole doublet with isomer shift δ = 2.09 mm.s -1 and a quadrupole splitting parameter (Δ) around 0.70 mm.s -1 , [START_REF] Nordstrom | [END_REF]38] amorphous (disordered) SnO for the Sn 2+ quadrupole doublet centered at δ = 2.96 mm.s -1 with a high Δ value (~1.6 mm.s -1 ) [11,39] and amorphous SnO2 for the Sn 4+ quadrupole doublet characterized by an isomer shift close to zero (δ = 0.06 mm.s -1 ). [11,[START_REF] Nordstrom | [END_REF] A better fit to the experimental data was achieved by considering both Sn 0 and Sn 4+ subspectra as the weighted sum of quadrupole doublets with Lorentzian shape (line width 0.90 mm.s -1 ) and the same isomer shift but different values of Δ, i.e., with a distribution of quadrupole splitting values. The Δ distributions, which reflect some local disorder or heterogeneity in the tin electronic environment and/or the occurrence of several tin sites, are then characterized by their shape (mono-or multi-modal pattern and extent) and a mean value (labelled with the * sign in the Table 2). The Sn 0 subspectrum exhibits a bimodal distribution of the quadrupole splitting parameter with a contribution at low values (associated with symmetrical electronic environment) and a broad component centered at about 1.0 mm.s -1 (Figure 8). This may reflect different environments for the tin nucleus depending on the distribution of tin and copper atoms in its surroundings, as expected in the η'-Cu6Sn5 crystalline network where three different sites have been identified for tin. [33,38] Furthermore, for copper-tin intermetallic compounds, the 119 Sn isomer shifts increase with the tin : metal ratio; for example, at room temperature, δ (Cu3Sn) = 1.71 mm.s -1 and δ (Cu6Sn5) = 2.20 mm.s -1 . [START_REF] Nordstrom | [END_REF]38] Thus, the Sn 0 subspectrum (Figure 8) may be attributed to a tin-copper alloy with a crystalline structure similar to η'-Cu6Sn5 but presenting tin vacancies, as suggested by PDF refinement and EDX analysis. Hence, the 119 Sn Mössbauer that the Sn-Cu NPs synthesized using TFSI - precursors present a core of intermetallic tin-copper alloy (51%), and a shell containing SnO (10%) and SnO2 (39%) at the outer surface in good agreement with the HAADF-STEM and EDS analyses. Concerning the electrochemical properties of Cu6Sn5, the theoretical capacity associated with lithium insertion for the stoichiometric compound is 605 mAh.g -1 . According to Larcher et al [40] , the electrochemical mechanism of bulk '-Cu6Sn5 proceeds via three types of lithium insertion reactions related to (i) a solid solution behavior, (ii) a partial extrusion of Cu leading to Li2CuSn and (iii) a complete extrusion of Cu ultimately leading to the lithium rich phase Li22Sn5. During the latter, Choi et al [41] showed that the reaction was limited to the Li7Sn2 composition. In bulk phases, steps (ii) and (iii) were associated to plateau region occurring at 0.4 and 0.1 V, respectively. The electrochemical properties of Cu6Sn3.31.7 were assessed using galvanostatic discharge/charge experiments (Figure 9a). The discharge/charge curves were obtained by cycling Cu6Sn3.31.7 electrode against metallic lithium under 100 mA.g -1 within the voltage range 0.05-2.0 V. The first discharge curve featured a sloping curve with a lack of plateau region and a capacity of 1086 mAh.g -1 largely exceeding the theoretical value. These two aspects were commonly observed for nanosized Cu6Sn5 with the extra capacity assigned to an irreversible conversion process of SnOx phases. [42][43][44][45] According to the phase's proportion (Cu6Sn5-, SnO, SnO2) determined by Mössbauer spectrometry, we calculated the theoretical capacity including the contribution of conversion and alloying reactions from SnOx phases. This led to a value of 967 mAh.g -1 close to that found for the first discharge (Table S2). During the first charge, a capacity of 576 mAh.g -1 was obtained. Moreover, most of this capacity was obtained within the low voltage region (<1V) which is characteristic of alloying processes, hence ruling out the contribution of conversion reactions in the overall lithiation mechanism. [46,47] Upon cycling, a stable capacity of 530 mAh.g -1 was maintained after 90 cycles. In the used electrode formulation, a large content of carbon was added that partially contributed to the overall capacity. To account for this contribution, we subtracted it leading to a capacity close to 400 mAh.g -1 (Figure 9b). This capacity value remained, however, lower than expected for a full utilization of the Sn matrix (Table S2) suggesting that some Sn were inactive probably those embedded in a Li2O matrix.

Conclusion

A direct synthesis of Sn and Sn-Cu alloy was developed by using metallic precursors and ionic liquid sharing the same anionic group that is TFSI -. This approach enabled to avoid side impurities typically encountered using chloride precursors and allowed to stabilize alloys. NMR relaxometry of 1 H (cation) and [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F (anion) further showed that NPs are surrounded by a first shell of neighbor constituted by cations of the IL. Using TFSI -precursor, we successfully prepared Sn-Cu alloy as opposed to the chloridesalt route which led to the precipitation of monometallic phases. This difference in reactivity was investigated by means of cyclic voltammetry measured on a solution containing different stoichiometries of Sn:Cu with the reduction potential (Gibbs energy) varying depending on the cation concentrations. The structure of the precipitated Sn-Cu alloy was investigated using PDF showing that it crystallized in the ' polymorph with Sn deficiency, i.e., the composition determined by structural analysis was Cu6Sn3.31.7, which was further confirmed by EDX analysis. Mössbauer spectrometry allowed us to assert the occurrence of SnOx phases located at the outer shell of the nanoparticles. The lithium insertion properties was assessed by galvanostatic cycling with a sloping voltage profile characteristic of NPs. The reversible capacity was explained by considering an alloying process.

Overall, this study demonstrated that the chemical system used is an effective route for the preparation of alloys and can be certainly extended to other elements.

Experimental Section

The synthesis of Sn-based compounds was performed following a published protocol. [11,48] All operations were performed in a glove box filled with argon (H2O and O2 content < 1 ppm). For the synthesis of metallic Sn, a 40mM solution of SnCl2 (99%, Alfa Aesar) or Sn(TFSI)2 (Alfa Aesar) was prepared by dissolving the salt in 1 mL of [EMIm + ][TFSI -] (99.5%, Solvionic). The reduction of Sn was initiated by mixing the Sn(II) solution and a 400 mM of NaBH4 in 1 mL of [EMIm + ][TFSI -] solution. For the synthesis of Cu-Sn alloy, a nominal composition of Cu6Sn5 was targeted. A 40 mM solution of Sn(TFSI)2 and Cu(TFSI)2 (Alfa Aesar) was prepared by dissolving cationic precursors in the targeted stoichiometry, in 1 mL of X-ray diffraction pattern were measured using a Rigaku Ultima IV X-ray diffractometer with a Cu Kα radiation (λ= 1.54059 Å) with a scan rate of 0.1°min -1 between 10° and 80° (2θ). The measurements of the 1 H and [START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F nuclear magnetic resonance (NMR) relaxation rates R1=1/ T1 have been carried out on a Stelar Spinmaster Fast Field Cycling (FFC) relaxometer. In this case, only R1 has been measured using a pre-polarized (PP) sequence from 10 kHz to 8 MHz and a non-polarized (NP) sequence from 10 MHz to 30 MHz. [49] The parameters used for the experiments were the following: 90° RF pulse duration: 8.5 (9.5) µs, the acquisition frequency: 15.8 MHz, for 1 H ( 19 F) relaxation measurements. The recycle delay between two consecutive acquisitions was set to fivefold the longest spin-lattice time at the highest relaxation field, the polarization time was set to fourfold the spin-lattice time at 25 MHz (referring to the 1 H resonance frequency). Magnetization values were recorded for 16 logarithmically spaced values of evolution times; in the whole frequency range, the evolution of magnetization was monoexponential within experimental error. The temperature value was set at 233K and checked before and after measurements to ensure a stability of ± 0.5 K.

The high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and simultaneously acquired energydispersive X-ray spectroscopy (EDX) elemental mapping analysis was performed on a JEM ARM200F cold FEG probe and image aberration corrected electron microscope operated at 200 kV and equipped with a large solid-angle CENTURIO EDX detector. TEM sample was prepared by crushing of material in agate mortar, dispersed in ethanol and following transferring suspension to a Ni holey carbon grid.

Cyclic voltammetry (CV) curves were recorded at 0.5 Vs -1 in the potential range of -0.6 and +0.4 V vs. Sn 2+ /Sn. All electrochemical measurements were performed in a glove box filled with argon (H2O and O2 content < 1 ppm). A three-electrode electrochemical cell controlled by a potentiostat (PAR 273A) was used. Mo (A = 0.503 cm²) foils was used as working electrode. The counter electrode was a Pt wire and a Sn bar was used as reference electrode. For solutions containing tin and copper, a second compartment was used with a 10 mM solution of Sn(TFSI)2 to ensure stable potential measurements.

High-energy X-ray data were collected at the 11-ID-B station at the Advanced Photon Source (Argonne National Laboratory) with an X-ray energy of 86.7 keV (λ=0.1430 Å). After corrections (background and Compton scattering), Pair Distribution Functions (PDFs), G(r) were extracted from the data using PDFgetX2 software. [50] Refinements of the PDF data were performed using PDFgui, [51] with structural models from ICSD (Inorganic crystal structure database) database. [52] Refined parameters were the instrument parameters, the lattice parameters, the atomic positions, atoms rate occupancy and the scale factor. The coherence length was refined using the spherical particle size parameter (spdiameter). The difference between the experimental observation (data) and the calculated values (model) correspond to the difference curve, which computes the quality of the refinement defined by the weighted Rfactor noted Rw. The R-value describes the difference between the experimental observation (data) and the calculated value (fit) for a single data point. 119 Sn Mössbauer measurements were carried out using a constant acceleration Halder-type spectrometer operating in transmission geometry with a room temperature 119m Sn (CaSnO3) source (370 MBq). Thin absorbers containing about 15 mg.cm -2 of Sn ( 119 Sn natural abundance 8.59%) were placed into a liquid helium bath cryostat. Spectra were recorded from room temperature down to 4.2 K, and the refinement of Mössbauer hyperfine parameters (δ isomer shift, Δ quadrupole splitting, Γ Lorentzian line width and relative areas) was performed using both homemade programs and the WinNormos software (Wissenschaftliche Elektronik GmbH). [53] The 119 Sn isomer shifts are referenced to BaSnO3 at room temperature.

The electrochemical properties of Sn-based alloy were investigated against metallic lithium using CR2032-type coin cells. The electrode formulation, adapted from Kravchyk et al [54] , was 30 wt.% of active material, 45wt.% of carbon (1:1 mixture of Timcal®, super C-65), and 25 wt.% of carboxymethyl cellulose CMC (Aldrich, Mw = 250 000). The electrolyte was 1 M LiPF6 dissolved in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (1:1 vol. %) with 2%wt. of fluoroethylene carbonate (FEC). The cells were assembled in a glove box filled with argon (H2O and O2 content < 1 ppm) with lithium metal as the anode and were cycled under 100 mA.g -1 in the voltage range of 2.0 -0.05 V vs. Li + /Li.

Figure 1 .

 1 Figure 1. X-ray diffraction powder patterns of the samples prepared using a) SnCl2 and b) Sn(TFSI)2 as precursors.

Figure 2 a

 2 and b display the 1 H and 19 F spin-lattice relaxation rate profile for [EMIm + ][TFSI -] at frozen state (T = -40 °C)

Figure 2 c

 2 and dshow the 1 H and[START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F NMR relaxation profile for a frozen (T=-40 °C) [EMIm + ][TFSI -] solution of -Sn. The striking feature is the strong modification of the QRE peaks at high frequencies on the 1 H profile. Instead of the two narrow peaks at 2.7 and 3.2 MHz, appears a broad and intense feature around 4.4 MHz. On the contrary,[START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F profile is weakly modified by the presence of metallic nanoparticles. The 1 H and[START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F NMR relaxation results suggest that only the cationic groups [EMIm + ] interact strongly with the surface of the nanoparticles. Furthermore, the same experiments were conducted on oxidized Sn nanoparticles dispersion in [EMIm + ][TFSI -]. In this case, both the 1 H and[START_REF] Kimmich | NMR: Tomography, Diffusometry, Relaxometry[END_REF] F profiles for oxidized Sn nanoparticles dispersion are superimposed to those of neat [EMIm + ][TFSI -] (FigureS2).

Figure 2 .

 2 Figure 2. Spin lattice relaxation rates, R1, as a function of the frequency for frozen (A) 1 H and (B) 19 F within neat [EMIm + ][TFSI -] and (C) 1 H and (D) 19 F within -Sn in [EMIm + ][TFSI -].

Figure 3 .

 3 Figure 3. X-ray diffraction pattern of the sample prepared from chloride Sn-Cu precursors.

Figure 4 .

 4 Figure 4. Cyclic voltammograms of [EMIm + ][TFSI -] solution containing a) 25 mM Sn(TFSI)2 or Cu(TFSI)2 and b) 50 mM of Sn(TFSI)2 and different content of Cu(TFSI)2.

Figure 5 .

 5 Figure 5. X-ray diffraction pattern of the sample prepared from TFSI -Sn-Cu precursors.

Figure 6 .

 6 Figure 6. PDF refinement of the sample prepared from TFSI -Sn-Cu precursors.

Figure 7 .

 7 Figure 7. (a) HAADF-STEM image of an isolated particle. (b) EDX elemental mapping for Sn L, Cu K, and O K and overlay color image (right corner) on several nanoparticles. The sample was prepared from TFSI -Sn-Cu precursors.

Figure 8 .Table 2 . 1 )

 821 Figure 8. 119 Sn Mössbauer spectra recorded at room temperature (a) and 4.2 K (b) of Sn-Cu alloy synthesized with TFSI -precursors. Dots represent the observed experimental data and solid lines the calculated spectra with three distinct components associated with tin-copper intermetallic phase and tin(II) or tin(IV) oxide. Insets: distributions of the quadrupole splitting parameter.

Figure 9 .

 9 Figure 9. a) Galvanostatic discharge-charge curves of Cu6Sn3.31.7 electrode cycled vs. Li + /Li. b) Evolution of the capacity as a function of cycle number for Cu6Sn3.31.7 electrode with and without the capacity contribution of carbon additive.

  ][TFSI -]. After the addition of a 400 mM of NaBH4 in 1 mL of [EMIm + ][TFSI -] solution, the mixture was stirred at room temperature for six hours. The powder was separated from the IL by centrifugation and then washed with acetone and water.

Table 1 .

 1 Structural parameters of the sample prepared from TFSI-precursors extracted from the PDF refinement. Structural parameters of the reference compound '-Cu6Sn5 were added for comparison purpose.

	Parameters	This work	'-Cu6Sn5
	Unit	cell
	parameters
	a (Å)		11.13(2)	11.022(5)
	b (Å)		7.38(1)	7.282(4)
	c (Å)		9.74(2)	9.827(2)
	beta		98.84	98.84
	V (Å 3 )		792.32	779.37
	Sn atomic
	occupancy
	Sn(1) -8f	0.53(8)	1.0
	Sn(2) -8f	0.75(8)	1.0
	Sn(3) -4e	0.75(9)	1.0

Acknowledgements

This article is based upon work from COST Action CA15209 EURELAX "European Network on NMR Relaxometry", supported by COST (European Cooperation in Science and Technology). Labex Michem and labex Matisse are gratefully acknowledged for the financial support. The work done at the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. The work done at the University of Warmia and Mazury in Olsztyn was financed by National Science Centre, Poland, grant number: UMO-2017/25/B/ST5/02348.

Entry for the Table of Contents

The use of a chemical system consisting of an ionic liquid (IL: [EMIm + ][TFSI -]) and metallic precursors based on TFSI -anionic groups enabled to prepare Sn-based alloys which could not be prepared using conventional chloride precursors.


Deema Kaneff

Monica Heintz

Introduction BESSARABIAN BORDERLANDS: ONE REGION, TWO STATES, MULTIPLE ETHNICITIES

D. Kaneff Max Planck Jnstitute for Social Anthropology, Halle, Germany & M. Heintz University of Paris X-Nanterre

In May 2003, the Governor from Odessa, accompanied by an entourage of other officiais, visited a •village situated in the most southern part of Odessa province, near the district capital of Reni on the Danube river, Uhaine. The occasion for the gathering of officiais was the opening of the gas pipeline in the district. The Governor began his speech in Russian with the statement 'People ask where is the Reniiski raion. And the answer is -at the end of Ukraine, almost in Romania!'. He then briefly paused and as an afterthought added 'sorry, shall I speak in Russian or Ukrainian?'. The loud chorus from the largely village audience confirmed that he should continue in Russian, while one man, leaned over to his neighbour and in good humour ridiculed the futility of giving the speech in any other language.

In these opening moments of the speech public acknowledgement was made of the geo administrative periphery of this southernmost tip of Ukraine. Language too was highlighted as a sensitive issue -a bone of particular contention in the traditionally Russian speaking Odessa region where inhabitants feel marginalised in the new Ukraine state that has failed to acknowledge Russian as the nation's second official language. The audience (ethnie Moldovans, Bulgarians, Gagauz, Russians and Ukrainians), perhaps more than the officiais, appreciated Russian as the only common Ianguage between them in this ethnically mixed region.

Political and economic reform across eastern Eurçpe and the former Soviet Union was accompanied by the dismantling/establishing of borders and the emergence of new nation states. Bessarabia, the region we are looking at in this volume, was until recently a part of the Soviet Union, with an interna) border extending across two statesthe Ukraiqian SSR and the Moldovan SSR. This internai border became an international border after I 991, following proclamations of independence by • the two Republics. At the same time, the strictly regulated border in the west established in 1944 between Romania and Soviet Union was relaxed after 1989, but is being reinforced again, in preparation for the admittance of Romania to the European Union due to take place in 2007. While the rise of new borders and nation-states are changes to be reckoned with in the region, this collection of articles also considers other boundaries that prove equally significant: boundaries of a historical, ethnie or economic nature, which delineate the area aJong different configurations. The crosscutting of political borders and ethnie and economic boundaries results in a shifting map of spaces and identities. While in some contexts the historically denoted region of Bessarabia is the significant unit, on other occasions the smaller unit of 'village' is the point of reference (be it a Moldovan, Bulgarian, Gagauz or ethnically mixed village). On other occasions, citizenship in the new nation-state is of central importance. 1

In this paper we consider borders in the most broad sense, that is, as both literai (ie actual geographical) l,orders anèi conceptual (socio-culturaJ) boundaries 2 . Bessarabia is� site of multiple borders and boundaries which 'delimit what is to be included and excluded ' (Rosier & Wendl 1999: 2). Thus 'borderlands represent a juncture between the literai and conceptual' borders (Rosier & Wendl: 226). In fact an important theme of the papers in this collection is that in order to understand this particular borderland region, we need to look at literai borders and conceptual boundaries as complementary processes that sometimes reinforce each other, sometimes subvert each other. Underlying this focus on the complementary relationship between litera) borders and conceptual boundaries is the recognition that such places are always areas of contested power (Wilson & Donnan 1998: I O & 26), a point highlighted by the changing • configuration of both borders and boundaries in Bessarabia. While it is clear that literai borders have changed over time, as various powers exerting influence over the area have either expanded or contracted their spheres of influence, conceptual boundaries, based on ethnicity and shared history, have remained more constant (although they too have changed). What is required is an exploration of how the construction and dismantling of state borders intersects with the formation• and dissolving of conceptual boundaries (Pelkmans, in press;Berdahl 1999). The aim of this collection is more modest: the papers that follow suggest that both boundaries and borders are being re-valued and used as a resource, particularly at such times of économie uncertainty. 3

This volume consists of a collection of essays that were originally presented at a workshop convened in March 2005 at the Max Planck Institute for Social Anthropology in Halle 4 . Many of the participant, s were local scholars working on the region from, a variety of academic backgrounds: history, sociology. and ethnology. But in every case the authors look at bourldaries or borders in the context of the new nation-states and economic hardship.

The first paper takes a historical perspective of economic relations in the region (Samkhvalov & Samkhvalov) while the second focuses on one type of economic activity -cross border trading (Polese). Migration based on ethnic/historical alliances is presented as a response to present difficulties (Ganchev and Demirdirek), while other authors (Anastasova and Boneva) identify the reverse process -an inward retreat by locals that rejects the integrating nationalising policies of the new states.

In the following section we look at the history of Bessarabia. Our intention is not to give a detailed or exhaustive record of the region's past, but to highlight the main borders and boundaries that exist in present day Bessarabia and identify their historical source. This allows us, in the section after, to look at how locals negotiate daily with these different borders and boundaries, calling on them in a variety of enterprising ways and using them to their advantage in the difficult economic situations. In the Conclusion we return to our wider concern: boundaries and borders as a strategic resource which varies in different contexts, where sometimes the nation-state, sometimes the region and sometimes the local village provide the guiding framework for local activities. 5

State borders and local boundaries

Bessarabia can be thought of as an 'institutionalised' borderland, in the sense that it has always been located in a peripheral position with respect to centres of political and often also economjc power.• In understanding the present position of Bessarabia as both a local 'centre' (for people living in• the area) and a periphery (econorrucally and politically, also an administrative/geographical periphery in the case of Ukraine), it is necessary to highlight a number of historical moments in the locality's past.

The Bessarabian region lies between the Prut, the Danube and the Nistru rivers, covering the vast part of what is now Moldova as well as the southwestern most part of Ukraine (south of Odessa to the Romanian border -see map below). The regional name 'Bessarabia' began its geopolitical existence in 1812, with the incorporation of the eastern part of the Romanian principality of Moldova into the Russian Empire following the Russian Turkish War of 1806-12. Previously the term had been used to designate only the southern part of Bessarabia that had belonged to the Romanian principality of Wallachia in the 14 th century (hence the name 'Bessarabia', which is derived from 'Besarab', the name of the ruling dynasty of Wallachia). Bessarabia was the target of large population influx from the mid-18 th century onwards. Before this it was sparsel r settled by Romanians and -from the end of the 17 1 century -also by Russian Old Believers escaping religious persecution in other parts of the Russian Empire). As part of the Russian Empire, the zone became the home to different groups: Bulgarians escaping repression from the Ottoman Empire, Gagauz, Germans, Poles and Jews. The new settlers were encouraged to settle by the granting of free land allotments (Gitelman, 1995).

Precisely because of the peripheral character of the region -located at the margins of the Ottoman and Russian Empires, it was a crossroad and frequently a battlefield -the place attracted those seeking religious and ethnie freedoms. In 1856, in the aftermath of the Crimean War, Russia lost the two most southern districts of Bessarabia to the prinçipality of Moldova, which united three years later with the principality of Wallachia to form the kingdom of Romania. But such an alliance was relatively short lived with the Russian Empire regaining the lost territory following the Russian Turkish war in 1878. It remained a Russian gubernia (province) until 1918 when the en tire Bessarabian area became once more subsumed by the Romanian kingdorrl. This was confirmed by the Treaty of Paris in 1919, but hever offücially recognised by the USSR (Livezeanu, 1995;[START_REF] King | The Moldovans. Romania, Russia and the politics of Culture[END_REF][START_REF] Fruntasu | 0 istorie etnopolitica a Basarabiei[END_REF]. In the 20 th century, the region was passed back and forth a number of times between the USSR and Romania. In 1940 the USSR used the guarantees given by the Ribbentrop-Molotov pact of non-aggression with Germany to occupy the region. In 1941, Romania used its new alliance with Germany to take it back. Finally in 1944, the USSR used its victory over Germany to incorporate the region into the Soviet Empire where it remained for almost 50 years. Romania renounced further claims to the region.

Bessarabia was thus incorporated relatively late into the USSR, in 1944. It missed out on the benefits of industrialisation that other parts of the USSR experienced after World War I, and the region entered the Soviet Union devastated by war and particularly underdeveloped. Severe famine ) and Stalin's deportations (several waves between 1941 and 1949) further disseminated the area. Further, entry into the USSR split the territory into two: the southern part was incorporated into the existing Ukrainian Soviet Socialist Republic, the northern and central parts, together with a strip of land situation between Nistru and Nipru (the region of Transnistria), made up the Moldovian Soviet Socialist Republic. This split between the two new Soviet republics was nominal in the sense that the border between them was internai (and not physically intrusive). But the incorporation of the region into the Soviet Union had far reaching implications. As new Soviet citizens, the inhabitants received passports which recorded, amongst other information, their membership in an official nationality 6 . Safeguard mechanisms were established to protect national minorities through administrative subunits (Hirsch 2005: 160), but immediately after the war, 'enemy-nationals', such as the Bulgarians, were in a particularly difficult position. One local response was to play up Soviet citizenship rather than nationality. The presence of internai borders didn't hinder travel across the Soviet Union for work, education or leisure activities. For example, during the 1980s, it was not uncommon for rural inhabitants from Bessarabia -often entire families -to move to Kazakstan or other Central Asian republics for work migration 7

. Others in the region fondly recall their holidays in Crimea or other more distant locations in the USSR. or their five years spent in one or another city while gaining a tertiary education. Of course travel across international borders, for example to sorne of the historical homelands (especially those countries not part of the socialist block), was much more difficult.

In the same way that national identity was always ultimately subsumed to a Soviet one, so the USSR was far more than a collection of nation-states. Soviet national republics were ultimately valued as parts of a larger political, economic and admini trative whole. The region was incorporated through a set of overarching economic, social and cultural policies, which transformed the area in fondamental ways. It enabled the continuation of exchange. lndeed, in many respects it increased exchange, for example educational and economic exchanges across the inner 'border' between the Moldovan and Ukrainian parts of the Soviet Union. It al o opened up the region to the far reaches of the Empire (especially at the Port sites, see Samkhvalov & Sarnkhvalov).

Economie integration became evident through common policies that resulted in the speciali ation of production and division of labour. This shaped the development of economic activities not only between the two republics but across the USSR, drawing ail Soviet republics into relations of mutual dependency.

After 199 l a process of devolution meant the dismantling of the USSR, which had been a centralised Union with a cornmon language, a common monetary currency, and integrated economic/political policies. This dismantling was essentially the reverse of the supranationalism being built up as the EU. The region, once well integrated into the USSR, is now divided between two independent states -Moldova and Ukraine. Two new capitals, Chisinau and Kiev, are trying to replace Moscow as national centres of political and administrative power. Previously 'internai' movement within the USSR has now been 'internationalized' (Brubaker 1992:269). The degree of economic integration of the region into the USSR became abundantly clear after 1991, when the economic dependency of the two new republics on Moscow, on each, and on other republics, posed a significant hurdle to independence. As we note below, both republics, but especially Moldova, remain intricarely dependent on areas now outside the new nation-state.

The newly established republics of Ukraine and Moldova promoted their titular nations through a variety of legi�lative acts, including the declaration of Ukrainian and (firstly Romanian and then) Moldovan respectively as their only state languages. At the sarne time, they introduced policies that promoted other ethnie groups as minorities. Despite moves to independence and the official replacement of the Russian language in administrative activities, Russian remains the 1 language of everyday interethnic communication ih Bessarabia. Further, the path towards Moldovan inllependence was less smooth than for Ukraine (although the latter also has its problems). Claims to independence by Moldovans, who are Romanian speakers, triggered anxiety amongst other ethnie groups. The response, sometimes involving outright conflict, included claims to autonomy by Gagauz (in the Gagauz Autonomous region -see Dernirdirek) and in Transnistria. As two separate countries belonging to the Commonwealth of Independent States, Ukraine and Moldova legally uphold free exchange relations and facilities for the movement of people within the limits of international regulations. However, there has been some flux. For example, the western and southern border between the newly dissected Bessarabia and Romania, which was well guarded during Soviet times, was relaxed in 1990. It has been reinforced more recently with the anticipated extenson of the EU frontier, due to Romania's imminent ascension to the European Union 8 . Although both new independent states have ambitions to join the EU, this is unlikely to take place in the near future and for now they remain outside 'Europe'.

Bessarabia remains a peripheral and marginal region. With respect to the Ukrainian part, the region is geographically as well as politically and administratively distant from Kiev-a fact openly acknowledged by officiais, as evident in the anecdote with which ;,e began this Introduction. Bessarabian Ukraine is also an economic periphery; the region has spiralled into decline, having received little support from Kiev in its bid to maintain the international activities of its Ports. Moldovan Bessarabia is also a periphery, due to its_ continued economic and political dependency on Moscow (to a lesser extent this is also evident in Ukraine and in many of the other former Soviet republics). Moldovan marginality is indicated, for example, in the fact that the headquarters of the most important Moldovan businesses are not situated in Moldova, but in Russia; in the fact that the embassies of most foreign states on which many Moldovans depend are not situated in Chisinau, but in Bucharest (an estimated 15-20% of the population are engaged in migration); and in the fact that the vast majority of the new Moldovan elites have been formed in Romania in the past fifteen years.

New citizenship rights are also a factor to consider. During the Soviet period, citizenship was granted to ail residents on Soviet territory. The national identity of each individual was recognised and featured in the Soviet passport -there was no differentiation in this respect between nationals from the titular nation of any Soviet republic and its co resident nationals. However, declarations of independence have been followed by different policies for defining citizenship belonging. Unlike the situation in Estonia, where citizenship was initially granted exclusively to ethnie Estonians and the large Russian minority became stateless, in the Republic of Moldova ail residents were entitled to Moldovan citizenship, regardless of their ethnie belonging, length of stay in the country or knowledge of Moldovan/Romanian [START_REF] Kolsto | National lntegration and Violent Conflict in Post-Soviet Societies: the Cases of E,stonia and Moldova[END_REF]. A similar situation exists in Ukraine. Nevertheless, the imposition of a new state language and the enforcement of a new nation state project has left non-titular ethnie groups in both countries suddenly marginalized. This has increased-to echo the movement of titular nations -their ethnie awareness. 9 Language remains a key issue in this context. For example, in Moldova e.,thnic min,prities have not, to date, adopted the state • Janguage, despite the state' s offer of free Moldovan language classes and an initial ruling that state employees must learn the language within five years (an obligation never enforced). The 'rninorities', who form 22% of Moldova's population, prefer to use Russian in the public sphere. 10 At the same time, minority status grants Bulgarians, Gagauz, Moldovans in Ukraine, and Ukrainians in Moldova • special access and claims to their historical 'homelands'. Here we find it useful to draw on [START_REF] Brubaker | Nationalism Reframed Nationhood and the National Question in the New Europe[END_REF], who identifies three important factors at play in eastern European nationalisms: the 'nationalizing state' (which has the project of building a nation state and state loyalties), 'national rninont1es populations' • (which are historically situated on the territory of the nationalizing state but do not belong to the majority ethnie group) and 'national homelands' (neighbouring countries to which national minorities could refer as 'their' nation state). The dynamics between these three factors determine the shape of most nationalist manifestations in eastern Europe. He further suggests that national minorities can 'alleviate' the pressure (for example, of linguistic homogenisation) coming from the nationalising state by maintaining their links with their homeland ( 1996). What is particular to Bessarabia is that most minority groups have not been created by a shift of borders, but by voluntary settlers who corne from countries that do not share borders with Ukraine and Moldova. In turn, this means that present migration and special access claims take on a particular form. For example, Gagauz Ukraines choose to migrate to Turkf!Y rather than any other country, because they say that their language skills make these places easier when se�kin� employment abroad.

Such relations with their historical 'homeland' (in some cases dormant for many decades) are now being activated, partly as a strategic response to Bessarabian marginality and econornic decline. An example is from the ethnie Bulgarian village of Nagorna (7 km from the Moldovan border in Ukraine): Kaneff learnt that the family of one of the Nagorna school teachers, who has worked and lives in Moldova since the 1980s, was applying for a Bulgarian passport. The family did not intend to live in Bulgaria; they simply reàlized that access to a Bulgarian passport would open doors in terms of migration and work in Europe (Bulgaria is due to become an EU member in 2007). Similarly, Heintz conducted a survey in the Moldovan village of Satu Vechi 11 and found that from a sample of JOO households, five contained members who held a Romanian passport. Of those, two spontaneously claimed that they needed the passport only for travelling to the EU for the purposes of car trafficking and not for asserting their Romanian identity. Two of the papers in this collection look precisely at how different ethnie groups in Bessarabia are using their minority status and links with another 'homeland' in order to alleviate their. economic situations. Such migration enables educational advantages (Bessarabian Bulgarians in Bulgaria -see Ganchev) or work opportunities (Moldovan Gagauz -. see Demirdirek).

Marginalisation through the attribution of 'ethnie minority' status gives non-titular ethnie groups minority status 'at home' and an opportunity to connect with the original/historical homeland. This serves to strengthen regionaJ, Bessarabian links, despite the fact that the area is now divided by an international border. Ties based on marriage, kinship and the practice of common rituals means that ethnie groups maintain links across the border. The Bulgarian schoolteacher mentioned above, for example, travels at least once a month to visit her Bulgarian sister and family in what is now a town across the border in Moldova.

In turn the 'Moldovan' (Bulgarian) nephews spend the en tire summer holidays with their aunt and grandmother in Nagorna. Birthdays, Christmas and New Year and a variety of other occasions bring the extended family together. Educational connections, based on people knowing each other during the Soviet period when they studied together (many in Ukraine Bessarabia obtained their university educations in Chisinau rather than the more geographically distant Odessa) provide close alliances between people now living 'across the border'. At the same time there has been an increased population flow for reasons of tracte (see, for example, Polese). In many cases, such cross border connections render the new nation-states 'irrelevant' through the mobilization of shared histories that temporally refer to pre-1991 times and the common use of the Russian language. Everyday border activities take place in Russian, the only common language across the two nations and between the different ethnie groups. The new state border is not undermined deliberately; rather there is a practical necessity for communication between kin and economic traders across the border. Exchanges based on shared history and economic activity often bypass the new international border.

Both new states try to re-focus their minority populations through educational policies that •attempt to mould a new generation of citizens who can speak Moldovan or Ukrainian. Also, through a variety of state sponsored ceremonies (such as national ho'lidays) which help to draw the periphery away from the border and refocus citizens inward to the centres of power. To some extent the legacies of Soviet policy, which designated the Moldovan part of Bessarabia agricultural, while encouraging industry in the Ukrainian sector (largely because of the location of the ports of Reni and Ismaiil) also strengthen new divisions in the area (see Samkhvalov& Samkhvalov) between the countries. A trip to southern Odessa province through the border zone, attests to assymetrical tendencies: the poorer Moldovans sel! agriculturaJ produce on the roadside to passing (Ukrainian) motorists.

Ethnicity in the region occurs in a distinct way, and many villages remain predorninantly monoethnic. Regional_ mix, however, is evident when considering a set of villages. For example, the district of Reni in Ukraine comprises 7 villages: one ethnically Bulgarian, one Gagauz and five Moldovan. This arrangement of predominantly monoethnic villages in districts made up of villages of various ethnicities has been retained over the past two centuries. Various arrangements that maintained the elhnic conlinuity of the villages are discussed by a nurnber of authors in this volume (see especially Boneva). For the last 50 years, Russian has served as the common language between ail ethnie groups. Thus. within each village the local ethnie language is rnaintained (Bulgarian, Moldovan etc), while Russian erves as the language of communication across ethnie boundaries.

The picture is further complicated by the fact that even neighbouring villages, which belong to the same ethnie group, display variations in language and ritual practices. This provides a potential source of local differentiation and means that in some contexts even ethnicity does not serve the purposes of regional unification. Thus while ethnie ties across the new border �tween different minority groups are reinforced in some contexts, in others internai differentiation within each ethnie group is prorninent. In Ukraine, Kaneff noted this at Christmas, which was celebrated on different dates and by different rituals not only by villages of different ethnicities but also by the same ethnicity. In Nagorna, for example, Christmas was celebrated on the 7 th January. In a neighbouring Moldovan village, it was celebrated on the 25 th December, while in yet another of the neighbouring Moldovan villages it was celebrated on both dates! Therefore, sorne rituals do not subject the local population to the state centre as rnuch as maintain local differences between cornmunities in the district.

In many respects Bessarabia displays rnany of the characteristics of a 'typical' borderland as both peripheral to the state centre and with unique local cultural and shared econornic relations with the other border cornmunities (Donnan & Wilson 1999: 5). What we have tried to emphasise in this section is the cornplicated intersection across literai borders and conceptÙal boundaries. These have a long history in Bessarabia and are changing ail the time. The present 'unity' of the region is based also on this shared history of resettlernent and migration by different ethnie populations during the l 8 th and 19 th centuriespeople who have lived together in the region since. Under the influence of various powers-Ottoman, Russian, Romanian, Soviet -these settlers have witnessed füe coming and going of rnany state borders, especially in the last century. Local ethnie boundaries based on •language, religion, rituals and economic exchange cross-eut literai borders: sometimes reinforcing them, sometimes rendering them irrelevant. Yet ethnie boundaries too are configured differently in different contexts: sometimes creating differentiation between members of the same ethnie group, sometimes aligning them togethér with respect to another ethnie group. The overall resulting picture is Of local communities that can be temporarily aggregated along different principles (ethnie, economic, linguistic and history) to serve the interests of the moment. The papers in the volume encourage us to examine how borders and boundaries are exploited locally.

They provide examples of when exactly borders and boundaries are unifying and when they are fragmenting forces.

Resourceful borders

In this section we look at how the everyday negotiation of borders and boundaries plays an instrumental rote in the way Bessarabians cope with the present difficult economic situation in the region. In so doing, we highlight particular themes in the papers, which essentially can be grouped into three topics: economic trade (Samkhvalov &. Samkhvalov and Polese), migration (Ganchev and Demirdirek) and retreat to the local (Boneva and Anastassova). Ail papers focus on either international, regional or village community borders/boundaries. Donnan & Wilson (1999: 87) view borders and their 'unique locational ambiguity' as a 'resource,' which those living in the vicinity can exploit. This seems equally true in our extended understandings of borders that include boundaries. The fact that Bessarabians now live in two states, but one historically defined region, and the multiple identities to which they have access is based on a long history of changing states and borders. It is also based on the effects of boundaries -minority status, tluency in various languages. Especially in difficult economic Limes loc�I people.. use their multiple identities and minority status (and different combinations of these identitfos), to develop strategies of survival.

For exarnple, an ethnie Bulgarian in the Ukraine state may be geographically, linguistically and ethnically marginalized from Kiev, but has official recognition as a member of a national minority group and a historical homeland (Bulgaria).

He may have Russian language skills and perhaps also networks of friends/family in Moldova (and therefore with possible exploitable connections to Romania). Such connections provide a potential resource in dealings with the state, in defining identities and negotiating strategies designed to cope with economic hardship.

Sorne of these 'resources' corne with official state backing -eg the privileges (and constraints) associated with minority status. Formai recognition is achieved through state support of various programmes that encourage local contacts with the historical homeland and through the provision of funding for the establishment of local museums that publicly display ethnic/historical origins. Other resources are founded in informai networks that compete with the state apparatus (eg cross border trading). As others have noted (eg. Wilson & Donnan 1998: 10, 21 ), the mobilization of connections that traverse state borders are not necessarily about the deliberate subversion of the new !,tates. Nevertheless, this may be a consequence, for many of these connections transcend the limits of the state and underline its weak position.

When an area is peripheral in geographical and administrative terms, the citizens in this area are often disadvantaged; political and economic resources controlled by the state centre may be harder to access. Minority groups are often structurally in a more distant position to the capital (eg through language disadvantages), adding to the difficulties of accessing resources. The situation is even more dire in a postsocialist context where wide ranging reforms have dismantled previous structures while new markets and political stability have yet to be guaranteed.

Two of the following papers deal specifically with economic activity: Samkhvalov & Samkhvalov take a historical perspective of large scale economic developments, showing the tluctuating fortunes of Reni and regional-national tensions in local attempts to engage in large scale cross-border trading. Polese focuses on small scale informai economic activity across the Ukraine Moldovan border.

Borderlands, Samkhvalov & Samkhvalov remind us, need not always be econornically peripheral regions. Indeed, Bessarabia, or more specifically the district of Reni, was a privileged area during the USSR; it was a crucial strategic transport node connecting Soviet Union to its international trading partners. In this sense the region was incorporated into the economic complex of the USSR through strong economic ties that not only provided economic wealth and stability, but helped maintain regional unity. The collapse of the Soviet Union has brought about a decline in the international . importance of this region through the running down of infrastructure and lost business for the Port. The region's present decline in status -from a main international transit site during Soviet times to a rural backwater with little international activity -is occurring despite local leadership attempts to boost local. economic developments through cross border cooperative ventures. One of the reasons for failure, Samkhvalov & Samkhvalov suggest, is the lack of support for such ventures at the national level. The newly created independent Ukraine perceives such expressions of local unity as a threat to its integrity. Local and national interests are not always aligned.

In this sense, Samkhvalov & Samkhvalov alert us to local-national tensions when regions attempt to assert initiative and a degree of autonomy in trading (see also Anastassova).

According to Samkhvalov & Samkhvalov, informai and undocumented small-scale trading is an important form of cross border activity with a Jong history that still thrives in the region. This is the central theme of Polese's paper on traders who move daily between Chisinau and Odessa by train. Polese shows how the inequalities in economic conditions between Moldova and Odessa, draws Moldovan traders to relatively abundant and cheap goods in Odessa. Polese reminds us that much like the border between Moldova and Ukraine, which is so flexible it is experienced differently whether onen travels by train or car, trade and 'corruption' can also be ambiguously interpreted. The boundary between illegal and legal activity is frequently unclear. Indeed local, petty trading activities benefit not only those directly engaged in the activity; political/economic elite and customs officiais are also beneficeries. For Polese, the big loser is the state, or at least those state organs, which suffer income loss through unregulated trading. When states are unable to provide economic security for their citizens, undocumented and often illegal cross border trading becomes a local necessity.

Cross border trading is a response to inequalities and shortages between two sides of the border. A more permanent response is migration. In his paper, Ganchev reminds us of the importance of minority s,tatus, which opens up possibilities of temporary or pe�manent migration through educational opportunities. His focus is on Bessarabian Bulgarians who exploit their ethnie connections in order to continue their higher education outside Ukraine, in Bulgaria. Ganchev does not look at the economic side of this migration (although we assume it to be an important dimension of students' motivation), but what is clear is that during the period of study, the visitors' identity as 'Bessarabian Bulgarians' (distinct from a Bulgarian identity) was reinforced, even strengthened, through a variety of practices -for example, speaking Russian amongst themselves rather than Bulgarian. In this way Ganchev shows us how a local Bessarabian identity is reasserted in a 'foreign' context.

The theme of the reproduction of a local Bessarabian identity through interaction with the historical 'homeland' is also the theme of Dernirdirek's paper on Moldovan Gagauz. She looks at the crossing of both literai borders and conceptual boundaries (through travel to Turkey and entertaining Turks in Moldova) as a way in which Gagauz reformulated their sense of collectivity. Much as in Ganchev's Bulgarian example, the importance of language as the source of collective struggle and identity • is highlighted in perpetuating the Bessarabian community with respect to the historical 'homeland'. Also much like the Bulgarian case, Demirdirek shows how Gagauz, with privileged access as a 'minority' in Moldova, exploit new educational and employment opportunities provided by another state (Turkey).

A reverse strategy that looks 'inward' is the theme of the final two papers in the collection. Here, the question of maintenance and continuity as a response to external pressure is addressed. As opposed to' the two previous papers which look at emigration and crossing of international borders as a way to deal with prèsent hardships in the region, here the opposite strategy is evident: turning away from the outside (and centres of nation-state power) to focus inwards. Boneva's historical account looks at two (ethnically Bulgarian) villages in Moldova and addresses the question of how they have maintained their identity over almost two -centuries. She attributes continuity to the maintenance of various practices (language, particular naming systems and so on) and suggests that these practices have survived over many generations largely as a result of local responses to outsider policies. The Russian Empire showed tolerance towards the settlers (until the 1860s) and after this locals were still able to avoid integration through non-engagment (eg by not attending or being unable to afford to go to school). The big changes came only after Bessarabia's inclusion into the Soviet Union after World War II, when free and compulsory educational programmes led to a graduai break up of endogamy. Agricultural reforms and modernisation were also relatively effective in integrating the region into the USSR. This however, did not bring about massive changes locally, since educated villagers moved out of rural areas. Meanwhile those who remained behind in rural Bessarabia were able to retain their distinguishing practices through a degree of isolation 12

• Only now, after over 100 years of isolation from their 'homeland', has there been a Moldovan recognition of rights of ethnie minorities. This has enabled the flourishing of local schools teaching minority languages. In short, it seems that despite the state apparatus (especially education) which has been. instrumental in attempts to incorporate fhe region into wider structures, local autonomy and ethnie markers/differences have been maintained through a variety of mechanisms despite pressures from the outside.

Anastassova furthers this theme of regional autonomy and inward focus. She describes a multiethnic village in Bessarabia (with a majority population of Russian Old Believers) at a historical moment when appeals to Bessarabian identity were particularly vocal and strong. Anastassova shows ushow claims to a Bessarabian identity represent both a retreat and rejection of outside reforms that were taking place in Ukraine in the 1990s. The 'retreat' to 'Bessarabianness' was a way to create a sanctuary in a world perceived as disintegrating and dangerous, where chaos and disorder reigned as a result of the gathering moment of postsocialist reforms. The path of local order and economic success was directed by the Head of the village cooperative, who refused to engage in wider reforms, but continued to offer villagers al! the benefits of the previous socialist system: protection, welfare, leadership and discipline. His ail pervading authority steered the village to economic stability and social security at a time when other areas experienced <lectine and chaos. A retreat to 'Bessarabia' was a strategy as well as response to the wider external crisis. In her paper, Anastassova thus speaks to the relationship between local and national, showing how externat reforms can bring about a regional reaction that is not always in line with national policy (something that Samkhvalov & Samkhvalov also show).

The papers reveal the ambiguous yet numerous resources that Bessarabians can draw on: most have access to more than one state and more than one identity. Tt1è-liminal' position that allows them to negotiate across various borders and boundaries gives them a set of possible 'resources' that can be used strategically. The playing field, however, is not equal: different ethnie groups within the region have uri equal access to political and administrative (if not also economic) powers. Thus despite the vast outnumbering of Moldovans in the Reni d�strict in Ukraine, Bulgarians appear more prominent in local administration. Bulgarians themselves attributed this fact to their more efficient language skills. They claim to speak better Russian than the Gagauz or Moldovans (because of the greater similarity between the Bulgarian and Russian Ianguages). Hence, they learn the language with greater ease and fluency than their Moldovan or Gagauz neighbours who speak with an �ccent. 13 This gave Bulgarians a greater political advantage during Soviet times and continues to do so in the present, since Russian is still informally the dominant language while similarities with Ukraine still provide an advanta & e• In theory, with Ukrainian now the official state language, ethnie Ukrainians have the upper hand, as do native Moldovan speakers in Moldova. 14 In short, different ethnie groups have different access to resources and power in the region at different moments in time.

A regional Bessarabian identity that cross cuts two nation-states and local village identities (and minority rights that gives privileged access to more distant historical 'homelands') are part of the everyday resources available to these borderland peoP.le and by which they negotiate their daily lives.

Conclusion: Strong ethnicities and histories, weak states?

Postsocialist reforms, the rise of new independent states and restrictions relating to the new EU border ail influence the particular relations that are b�ing played out between the periphery and the centre in Be�sarabia, between 'border people and their politicat' core' (Wilson & Donnan 1998: 21 ). In conclusion, we underline a few tendencies concerning the strategic use of borders and boundaries.

If borders and boundaries are a resource to be used strategically, then in Bessarabia, the power of this resource resides in its ambiguity. There is, firstly, the ambiguity of the 'political core'. The incorporation of the region into the Soviet Union after World War II gave the zone a clear 'political core'. However today, the situation is more complex and it is apparent that there is no one 'centre'.

Competing loyalties, multiple identities and the historically based connections tying the region to various powers at various periods in the past mean that there is no one centre of economic and political domination 1 5 • Rather, the people of the region have a wide set of connections with a variety of centres: Kiev, Chisinau, Moscow, Sofia, Bucharest as well as Odessa. The new national capitals pose alternative links to Moscow and Odessa but their pull is, if anything, weaker -for reasons of language, past connections and networks, and because of the economic opportunities offered to labour migrants in Moscow. The historical 'homelands' of Buigaria, Romania and Turkey are also attractive with their promise of education, employment and better opportunities in a setting that is not totally foreign.

Economie activities, once incorporated the area into the Soviet Union, have unravelled, adding to the region's marginality. Now lacking in international importance, economic activity appears to reinforce regional Bessarabian unity, often at the expense of the new international border between Moldova ând Ukraine. This is largely achieved thro• ugh informai trading act1v1t1es. Economie . marginalisation and decline is also evident in migration patterns; people are often forced to look beyond the nation-state. Often undocumented migration, which tlouts state authority and law, serves to reinforce Bessarabian regional unity through migration to historical homelands (Bulgaria, Romania, Turkey). Indeed local villagers openly express disregard for the international border between Moldova and Ukraine; for example, they have been known to swap passports, or borr�w a friend's, when they wish to cross the border to visit family/relatives and their own is not at hand.

Boundaries created by rituals and spoken languages serve to both fragment the region into its constituent village units, and bind it into a presented whole. Often, differing social practices within the same ethnie group fragment the region into village 'units'. For example, communities express their uniqueness through particular versions of the same practice (different dialects, times to celebrate Christmas and so on). A display of unity (on the basis of ethnicity) often occurs through group presentations to outsiders -to state officiais and visiting dignitaries from the historical homelands. Minority status -a prerequisite for EU membership grants a particular way for local people to be accepted and disciplined into the nation-state. At the same time, it grants them legitimate access to alternate (historically rooted) homelands. Government policies that sponsor 'minorities' are implemented in parallel with programmes of integration through the educational system and forced imposition of the nation's single language policies in public spaces.

In the context of strong ethnic/historical links and in'." a time' of globalisation and EU supranationalism, it seems-particularly difficult for the new states (Moldova or Ukraine) to establish themselves. How can state borders be strengthened in the face of transnational movements and expressions of loyalties that are connected to long and emotionally loaded histories that play to identities of origin? Or in the face of breakaway groups who make claims to autonomy, such as Transnistria? What the following papers suggest is that the new Moldovan and Ukraine states have not, to date, been particularly successful in creating strong borders. Nor have they been outstandingly successful in capturing their citizens' loyalties.

Notes

1 The use of the term 'Bessaral;>ia' is unproblematic in present day Ukraine but disputed by others in the region, notably in the former Moldovan SSR (where the term is avoided because it is taken to refer to the Romanian kingdom between the two world wars). We use this term because it is unproblematic for the local communities studied by the researchers in this volume (as well as to many scholars outside Moldova).

2 Or to use Donnan and Wilson's terminology (1998: 26), we are looking at both symbolic and state boundaries.. To distinguish between the two in this Introduction, we use literai boundaries to refer to actual state 'borders', while conceptual ones are denoted as 'boundaries'. When speaking of conceptual boundaries, we are not looking at the symbolic significance of the geographical state boundaries, ,but at other markers such as ethnicity or language, whicp, with the rise of the new postsocialist states, peed to be considered alongside these physical/literal boundaries. 3 Verdery showed that in Remania in times of scarcity people access resources through local ethnie connections ( 1996). In the same way papers in this collection indicate that the play on ethnicity is important, although the cases here indicate that connections along ethnie lines are more likely to be international rather than local. For instance ethnie Gagauz in Moldova will get economic help from Turkey rather than from ethnie Gagauz in Ukrainian Bessarabia (see paper by Demirdirek). 4 These papers constitute only a part of those presented at the workshop we convened, titled: Emerging citizenship and contested identities between the Dniester, Prut and Danube Rivers. We regret that A. Prigarin was unable to provide his paper for publication in this volume. The other papers on the topic of citizenship are brought together in an edited volume by M. Heintz, in preparation under the title "Weak State, Uncertain Citizenship: Moldova". 5 We thank M. Pelkrnans for reading and commenting on an earlier version of this paper. 6 Hirsch (2005: 324) shows how these ail important nationality categories had lasting impact as a 'rallying point' in post 1991 events, including in the emergence of the new republics. 7 In the village of Nagorna, Ukraine, Kaneff noted that 12 families had gone as work migrants to Kazakstan in the late 1970s and early J 980s and remained there for a decade, compelled to return only after 1991. 8 Citizens of the Republic of Moldova, who presently enjoy open access to Remania, will see the introduction of the Romanian visa regime in January 2007. 9 This increase i� ethnie awareness is not a specificity of the Bessarabian region but widespread throughout the former USSR territory since the 1980s. However, it is exacerbated by the lack of power and the lack of legitimacy of the emerging states (neither Moldova nor Ukraine have a tradition of independence). The situation is more dramatic in Moldova than in Ukraine, evident by the example of the separatist region of Transnistria, de facto independent while de jure part of the Republic of Moldova [START_REF] Troebst | We Are Transnistrians!" Post Soviet Identity Management in the Dniester Valley[END_REF]. At the beginning of the 1990s, Transnistria, the strip of land east of the Nistru river, parted with Moldova on the grounds of ethnicity. Inhabited by 60% russophones (Ukrainians and Russians), Transnistria protested the Moldovan movement of "national awakening" that ultimately led to the constitution of independent Moldova. Researchers suggest that ethnie contlict was an excuse for a power struggle between communist elites [START_REF] Troebst | The 'Transnistrian Moldovan Republic': From Contlict-Driven State Building to State-Driven Nation-Building[END_REF]. 10 Indeed the Party of Communists of Moldova won the 2001 elections campaigning on the reintroduction of Russian as state language and received considerable support from ethnie minorities. The question here is clearly not simply one of ethnicity, since Russians constitute only 5% of the Moldovan population (cf 2004 census). It is much more a question of historical and social alliances and perhaps also cognitive effort and convenience (it is not easy for a Gagauz, native speaker of a Turkish language to learn Romanian, a Latin langauge, after having obtained his/her education in Russian, a Slavic language, also written in cyrillics). The head of the Department for Ethnie Minorities, one of the rare Russophones speaking Romanian, narrated the problems she was facing when trying to convince her 9 year old daughter of the need to learn Romanian. Her daughter refused to learn Moldovan on the grounds that "ail her aquintances knew Russian". This situation continued until they made a trip to Romania (where the mother was conducting business) and the child faced the Romanians' ignorance of her native Russian Ianguage. Her mother convinced her child to learn Romanian, not because Moldovans spoke this language, but because Romanians did not speak any other! 11 Not the real name of the village. 12 Reviewing two hundred years of Bessarabian history, Fruntasu emphasises the fact that local communities retreated inwards and that this retreat impeded the creation of a larger (regional, national) identity, even in cases when forging an identity was on the agenda of the state in power [START_REF] Fruntasu | 0 istorie etnopolitica a Basarabiei[END_REF]. This ressembles the circumstances of 19 th century France when regions such as Ariège resisted their integration into the French state, despite the fact that there were no historical quarrels or ethnie conflicts that would have questioned France's authority over the area [START_REF] Weber | Peasants into Frenchmen: The Modernization of Rural France 1870-1914[END_REF]. 13 Persona) communication, Kaneff, 2003. 14 Inequalities in language skills has wide ranging implications: Kaneff witnessed the daily exclusion of villagers as a result of government policy that sponsors one language officially (Ukrainian). For example, in the municipal council, villagers sign legal documents (everything from marriage certificates to land tille deeds) without full y knowing what they are signing, since the documents are in Ukrainian and no translations are available. 15 ' .•• borèier people have identities which are shifting and multiple, in ways which are multivocal and multilocal .. .' (Donnan & Wilson 1999: 64).