supplementary materials


Acta Cryst. (2013). E69, i38    [ doi:10.1107/S1600536813013603 ]

Na2.9KMo12S14: a novel quaternary reduced molybdenum sulfide containing Mo12 clusters with a channel structure

P. Gougeon, P. Gall and D. Salloum

Abstract top

The crystal structure of trisodium potassium dodecamolybdenum tetradecasulfide, Na2.9 (2)KMo12S14, consists of Mo12S14S6 cluster units interconnected through interunit Mo-S bonds and delimiting channels in which the Na+ cations are disordered. The cluster units are centered at Wyckoff positions 2d and have point-group symmetry 3.2. The K atom lies on sites with 3.2 symmetry (Wyckoff site 2c) between two consecutive Mo12S14S6 units. One of the three independent S atoms and one Na atom lie on sites with 3.. symmetry (Wyckoff sites 4e and 4f). The other Na atom occupies a 2b position with -3.. symmetry. The crystal studied was a merohedral twin with refined components of 0.4951 (13) and 0.5049 (13).

Comment top

In a previous paper, we reported the synthesis, the crystal structures and, the physical properties of the compounds K1 + xMo12S14 (x= 0, 1.1, 1.3, and 1.6) which crystallize in a new structural type only based on the Mo12 cluster (Picard et al., 2006). We present here the crystal structure of the sulfide Na2.9KMo12S14 which is isomorphous with the latter compounds (Picard et al., 2006). Its crystal structure (Fig. 1) contains Mo12Si14Sa6 cluster units (for details of the i- and a-type ligand notation, see Schäfer & von Schnering (1964)). The i-type ligands cap Mo triangular faces and the a-type ones are in apical position for the external Mo1 atoms (Fig. 2). The Mo12S14 cluster unit is centred at a 2 d (D3 or 32 symmetry) position. The Mo—Mo distances within the Mo12 clusters are 2.6296 (5) Å for the distances in the triangles formed by the Mo1 related through the threefold axis and 2.6764 (4) in the triangles formed by the Mo2 atoms. The distances between the triangles formed by the Mo1 and Mo2 atoms are 2.7155 (4) and 2.7803 (4) Å and those between the two Mo23 triangles, 2.6440 (5) and 2.6745 (5) Å. The sulfur atoms bridge either one [S1 and S3] or two [S2] Mo triangular faces of the clusters. Moreover the S1 atoms are linked to a Mo atom of a neighboring cluster. The Mo—S bond distances range from 2.3855 (10) to 2.5907 (7) Å. Each Mo12S14 unit is interconnected to 6 adjacent ones via Mo1—S1 bonds to form the three-dimensional Mo—S framework, the connective formula of which is Mo12Si8Si-a6/2Sa-i6/2. It results from this arrangement that the shortest intercluster Mo1—Mo1 distance between the Mo12 clusters is 3.4025 (3) Å, indicating only weak metal-metal interaction. The Na cations reside in large channels extending along the c axis (Fig. 3). The Na1 cations occupied distorted tri-capped trigonal prismatic cavities of sulfur atoms and the Na2 are in an octahedron compressed along the threefold axis. The Na—S distances spread over a wide range 3.210 (12) - 3.898 (11) Å. The K cation is eight-coordinated with six S2 atoms at 3.4188 (7), forming an octahedron compressed along the threefold axis, and the remaining two S3 atoms capping two opposite faces of the octahedron at 2.9460 (13).

Related literature top

For a previous report on the compounds K1 + xMo12S14 (x = 0, 1.1, 1.3, and 1.6), see: Picard et al. (2006). For details of the i- and a-type ligand notation, see: Schäfer & von Schnering (1964). For the program JANA2000, see: Petříček & Dušek (2000). The twinning was identified using the TwinRotMat routine of PLATON (Spek, 2009).

Experimental top

Single crystals of Na2.9KMo12S14 were obtained by treating crystals of KMo12S14 in a basic reducing solution of Na2S2O3/NaOH at 333 K for 3 days. The KMo12S14 compound was prepared by oxidation of single crystals of K2.3Mo12S14 in an aqueous solution of iodine at 363 K for 48 h. Single crystals of K2.3Mo12S14 were prepared from a mixture of K2MoS4, MoS2, and Mo with the nominal composition K2Mo3S4. The initial mixture (ca 5 g) was cold pressed and loaded into a molybdenum crucible, which was sealed under a low argon pressure using an arc welding system. The charge was heated at the rate of 300 K/h up to 1773 K, temperature which was held for 6 h, then cooled at 100 K/h down to 1373 K and finally furnace cooled. All handlings of materials were done in an argon-filled glove box.

Refinement top

In the first stage of the refinement, the atomic positions of the Mo and S atoms were deduced from those in KMo12S14 (Picard et al., 2006). A subsequent difference-Fourier synthesis reveals the potassium atom and a quasi-continuous electron density along the c axis due to the sodium atoms. The latter was modelled with two partly occupied sodium sites (4 e and 2 b positions) using second-order tensors for the anisotropic displacement parameters. Anharmonic treatment of the Na1 and Na2 atoms using the program JANA2000 (Petříček & Dušek, 2000) was unsuccessful. The final occupation factors for the Na atoms were refined freely. The highest peak and the deepest hole in the final Fourier map are located 1.07 Å from Na2 and 0.58 Å from Mo2, respectively. Analysis of the intensity data using the TwinRotMat routine of PLATON (Spek, 2009) revealed the studied crystal was twinned by merohedry with [100, 010, 001]as the twin matrix. The ratio of the twin components was refined to 0.4951 (13):0.5049 (13). The Na content found seems reliable since the cationic electron transfer towards the Mo12 cluster deduced from our refinement is +3.9 and is in agreement with the maximal limit of +4 that the Mo12 cluster can accept to be well bonded and with the semi-conductor behavior observed on a single-crystal. Indeed, a lower stoichiometry in Na would lead to a metallic behavior. This is also confirmed by semi-quantitative analyses by energy dispersive spectroscopy (eds) which indicated roughly stoichiometries comprised between 2.6 and 3.2 for the Na content.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: COLLECT (Nonius, 1998); data reduction: EVALCCD (Duisenberg, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Bergerhoff, 1996); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. : View of Na2.9KMo12S14. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. : Plot showing the atom-numbering scheme of the Mo12S14S6 cluster units. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 3] Fig. 3. : View of Na2.9KMo12S14 along the c axis showing the channels. Displacement ellipsoids are drawn at the 50% probability level.
Trisodium potassium dodecamolybdenum tetradecasulfide top
Crystal data top
Na2.90KMo12S14Dx = 4.575 Mg m3
Mr = 1705.89Mo Kα radiation, λ = 0.71069 Å
Trigonal, P31cCell parameters from 5780 reflections
a = 9.3664 (1) Åθ = 3.5–39.8°
c = 16.2981 (2) ŵ = 7.24 mm1
V = 1238.26 (2) Å3T = 100 K
Z = 2Multi-faceted crystal, black
F(000) = 15580.08 × 0.07 × 0.07 mm
Data collection top
Nonius KappaCCD
diffractometer
2536 independent reflections
Radiation source: fine-focus sealed tube2376 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.056
φ scans (κ = 0) + additional ω scansθmax = 39.8°, θmin = 3.5°
Absorption correction: analytical
(de Meulenaer & Tompa, 1965)
h = 1616
Tmin = 0.550, Tmax = 0.572k = 1616
37291 measured reflectionsl = 2927
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.027 w = 1/[σ2(Fo2) + (0.029P)2 + 4.9317P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.073(Δ/σ)max = 0.001
S = 1.13Δρmax = 2.74 e Å3
2536 reflectionsΔρmin = 1.84 e Å3
52 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.00032 (9)
Crystal data top
Na2.90KMo12S14Z = 2
Mr = 1705.89Mo Kα radiation
Trigonal, P31cµ = 7.24 mm1
a = 9.3664 (1) ÅT = 100 K
c = 16.2981 (2) Å0.08 × 0.07 × 0.07 mm
V = 1238.26 (2) Å3
Data collection top
Nonius KappaCCD
diffractometer
2536 independent reflections
Absorption correction: analytical
(de Meulenaer & Tompa, 1965)
2376 reflections with I > 2σ(I)
Tmin = 0.550, Tmax = 0.572Rint = 0.056
37291 measured reflectionsθmax = 39.8°
Refinement top
R[F2 > 2σ(F2)] = 0.027Δρmax = 2.74 e Å3
wR(F2) = 0.073Δρmin = 1.84 e Å3
S = 1.13Absolute structure: ?
2536 reflectionsFlack parameter: ?
52 parametersRogers parameter: ?
0 restraints
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Mo10.50983 (3)0.16646 (3)0.043656 (15)0.00973 (6)
Mo20.66853 (3)0.16929 (3)0.183610 (15)0.00826 (5)
S10.68780 (10)0.04088 (9)0.05564 (4)0.01069 (11)
S20.36482 (9)0.02520 (9)0.17966 (4)0.01064 (11)
S30.66670.33330.06924 (8)0.0129 (2)
K10.66670.33330.25000.0195 (3)
Na10.00000.00000.1936 (13)0.36 (4)0.71 (5)
Na20.00000.00000.099 (3)0.40 (4)0.74 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mo10.01224 (10)0.01354 (11)0.00434 (9)0.00714 (8)0.00045 (7)0.00041 (7)
Mo20.01081 (9)0.01033 (10)0.00371 (9)0.00535 (8)0.00034 (6)0.00060 (7)
S10.0143 (3)0.0125 (3)0.0063 (2)0.0074 (2)0.0003 (2)0.00134 (19)
S20.0121 (2)0.0118 (2)0.0064 (2)0.0047 (2)0.0014 (2)0.0007 (2)
S30.0172 (3)0.0172 (3)0.0044 (4)0.00859 (16)0.0000.000
K10.0264 (5)0.0264 (5)0.0058 (6)0.0132 (3)0.0000.000
Na10.47 (6)0.47 (6)0.12 (2)0.24 (3)0.0000.000
Na20.045 (4)0.045 (4)1.12 (12)0.023 (2)0.0000.000
Geometric parameters (Å, º) top
Mo1—S32.3855 (10)S3—Mo1iii2.3855 (10)
Mo1—S1i2.4620 (8)S3—Mo1i2.3855 (10)
Mo1—S12.4822 (8)K1—S32.9460 (13)
Mo1—S1ii2.4944 (8)K1—S3vii2.9460 (13)
Mo1—S22.5907 (7)K1—S2viii3.4188 (7)
Mo1—Mo1iii2.6296 (5)K1—S2ix3.4188 (7)
Mo1—Mo1i2.6296 (5)K1—S2x3.4188 (7)
Mo1—Mo22.7155 (4)K1—S2ii3.4188 (7)
Mo1—Mo2i2.7803 (4)K1—S2xi3.4188 (7)
Mo2—S12.4589 (7)K1—S2xii3.4188 (7)
Mo2—S22.4655 (7)Na1—Na21.55 (5)
Mo2—S2iii2.4904 (8)Na1—Na1xiii1.84 (4)
Mo2—S2iv2.5866 (7)Na1—S2xiv3.3131 (17)
Mo2—Mo2v2.6440 (5)Na1—S2xv3.3131 (17)
Mo2—Mo2iv2.6745 (5)Na1—S1xvi3.856 (12)
Mo2—Mo2iii2.6765 (4)Na1—S1xvii3.856 (12)
Mo2—Mo2i2.6765 (4)Na1—S1i3.856 (12)
Mo2—Mo1iii2.7803 (4)Na1—S2xviii3.898 (11)
S1—Mo1iii2.4620 (8)Na1—S2xiii3.898 (11)
S1—Mo1ii2.4944 (8)Na1—S2xix3.898 (11)
S1—Na2vi3.210 (12)Na2—S1i3.210 (12)
S2—Mo2i2.4904 (8)Na2—S1xvi3.210 (12)
S2—Mo2iv2.5866 (7)Na2—S1xvii3.210 (12)
S2—Na13.3131 (17)Na2—S2xiv3.56 (2)
S2—K1ii3.4188 (7)Na2—S2xv3.56 (2)
S3—Mo1—S1i92.320 (19)Mo1iii—S1—Mo1ii127.81 (3)
S3—Mo1—S191.819 (19)Mo1—S1—Mo1ii84.55 (3)
S1i—Mo1—S1169.89 (3)Mo2—S1—Na2vi99.6 (9)
S3—Mo1—S1ii89.07 (3)Mo1iii—S1—Na2vi98.08 (6)
S1i—Mo1—S1ii93.84 (4)Mo1—S1—Na2vi160.3 (4)
S1—Mo1—S1ii95.45 (3)Mo1ii—S1—Na2vi114.5 (6)
S3—Mo1—S2171.28 (3)Mo2—S2—Mo2i65.37 (2)
S1i—Mo1—S284.81 (3)Mo2—S2—Mo2iv63.873 (19)
S1—Mo1—S289.74 (2)Mo2i—S2—Mo2iv62.735 (18)
S1ii—Mo1—S299.32 (2)Mo2—S2—Mo164.912 (19)
S3—Mo1—Mo1iii56.554 (16)Mo2i—S2—Mo166.315 (19)
S1i—Mo1—Mo1iii118.03 (2)Mo2iv—S2—Mo1118.36 (3)
S1—Mo1—Mo1iii57.50 (2)Mo2—S2—Na1154.66 (8)
S1ii—Mo1—Mo1iii131.58 (2)Mo2i—S2—Na189.74 (2)
S2—Mo1—Mo1iii117.822 (17)Mo2iv—S2—Na1101.5 (3)
S3—Mo1—Mo1i56.554 (16)Mo1—S2—Na1110.7 (3)
S1i—Mo1—Mo1i58.24 (2)Mo2—S2—K1ii92.19 (2)
S1—Mo1—Mo1i117.29 (2)Mo2i—S2—K1ii150.01 (3)
S1ii—Mo1—Mo1i130.870 (19)Mo2iv—S2—K1ii90.10 (2)
S2—Mo1—Mo1i115.293 (18)Mo1—S2—K1ii123.66 (3)
Mo1iii—Mo1—Mo1i60.0Na1—S2—K1ii109.13 (14)
S3—Mo1—Mo2119.13 (2)Mo1iii—S3—Mo166.89 (3)
S1i—Mo1—Mo2113.78 (2)Mo1iii—S3—Mo1i66.89 (3)
S1—Mo1—Mo256.254 (17)Mo1—S3—Mo1i66.89 (3)
S1ii—Mo1—Mo2137.91 (2)Mo1iii—S3—K1140.47 (2)
S2—Mo1—Mo255.315 (17)Mo1—S3—K1140.47 (2)
Mo1iii—Mo1—Mo262.662 (9)Mo1i—S3—K1140.47 (2)
Mo1i—Mo1—Mo291.183 (8)S3—K1—S3vii180.0
S3—Mo1—Mo2i116.65 (2)S3—K1—S2viii70.407 (11)
S1i—Mo1—Mo2i55.546 (18)S3vii—K1—S2viii109.593 (11)
S1—Mo1—Mo2i114.41 (2)S3—K1—S2ix109.593 (11)
S1ii—Mo1—Mo2i138.42 (2)S3vii—K1—S2ix70.407 (11)
S2—Mo1—Mo2i55.112 (17)S2viii—K1—S2ix171.43 (2)
Mo1iii—Mo1—Mo2i89.759 (7)S3—K1—S2x109.593 (11)
Mo1i—Mo1—Mo2i60.181 (8)S3vii—K1—S2x70.407 (11)
Mo2—Mo1—Mo2i58.275 (11)S2viii—K1—S2x63.43 (2)
S1—Mo2—S293.26 (3)S2ix—K1—S2x109.349 (11)
S1—Mo2—S2iii87.06 (3)S3—K1—S2ii70.407 (11)
S2—Mo2—S2iii173.83 (2)S3vii—K1—S2ii109.593 (11)
S1—Mo2—S2iv117.76 (2)S2viii—K1—S2ii109.349 (11)
S2—Mo2—S2iv90.68 (3)S2ix—K1—S2ii63.43 (2)
S2iii—Mo2—S2iv94.62 (3)S2x—K1—S2ii78.22 (2)
S1—Mo2—Mo2v144.46 (2)S3—K1—S2xi109.593 (11)
S2—Mo2—Mo2v120.668 (19)S3vii—K1—S2xi70.407 (11)
S2iii—Mo2—Mo2v60.414 (17)S2viii—K1—S2xi78.22 (2)
S2iv—Mo2—Mo2v56.852 (18)S2ix—K1—S2xi109.349 (11)
S1—Mo2—Mo2iv150.83 (2)S2x—K1—S2xi109.349 (12)
S2—Mo2—Mo2iv60.265 (17)S2ii—K1—S2xi171.43 (2)
S2iii—Mo2—Mo2iv120.634 (19)S3—K1—S2xii70.407 (11)
S2iv—Mo2—Mo2iv55.862 (18)S3vii—K1—S2xii109.593 (11)
Mo2v—Mo2—Mo2iv60.428 (12)S2viii—K1—S2xii109.349 (11)
S1—Mo2—Mo2iii115.260 (19)S2ix—K1—S2xii78.22 (2)
S2—Mo2—Mo2iii117.738 (19)S2x—K1—S2xii171.43 (2)
S2iii—Mo2—Mo2iii56.865 (19)S2ii—K1—S2xii109.349 (11)
S2iv—Mo2—Mo2iii117.009 (17)S2xi—K1—S2xii63.43 (2)
Mo2v—Mo2—Mo2iii60.350 (10)Na2—Na1—Na1xiii180.000 (2)
Mo2iv—Mo2—Mo2iii89.670 (5)Na2—Na1—S2xiv86.1 (4)
S1—Mo2—Mo2i119.02 (2)Na1xiii—Na1—S2xiv93.9 (4)
S2—Mo2—Mo2i57.760 (19)Na2—Na1—S286.1 (4)
S2iii—Mo2—Mo2i116.843 (19)Na1xiii—Na1—S293.9 (4)
S2iv—Mo2—Mo2i115.061 (17)S2xiv—Na1—S2119.54 (9)
Mo2v—Mo2—Mo2i90.323 (5)Na2—Na1—S2xv86.1 (4)
Mo2iv—Mo2—Mo2i59.222 (10)Na1xiii—Na1—S2xv93.9 (4)
Mo2iii—Mo2—Mo2i60.0S2xiv—Na1—S2xv119.54 (9)
S1—Mo2—Mo157.07 (2)S2—Na1—S2xv119.54 (9)
S2—Mo2—Mo159.773 (17)Na2—Na1—Na2xiii180.000 (2)
S2iii—Mo2—Mo1115.73 (2)Na1xiii—Na1—Na2xiii0.000 (2)
S2iv—Mo2—Mo1147.71 (2)S2xiv—Na1—Na2xiii93.9 (4)
Mo2v—Mo2—Mo1147.951 (10)S2—Na1—Na2xiii93.9 (4)
Mo2iv—Mo2—Mo1111.157 (13)S2xv—Na1—Na2xiii93.9 (4)
Mo2iii—Mo2—Mo190.180 (8)Na1—Na2—S1i102.6 (9)
Mo2i—Mo2—Mo162.075 (8)Na1—Na2—S1xvii102.6 (9)
S1—Mo2—Mo1iii55.650 (19)S1i—Na2—S1xvii115.4 (7)
S2—Mo2—Mo1iii116.776 (19)Na1—Na2—S1xvi102.6 (9)
S2iii—Mo2—Mo1iii58.573 (17)S1i—Na2—S1xvi115.4 (7)
S2iv—Mo2—Mo1iii151.11 (2)S1xvii—Na2—S1xvi115.4 (7)
Mo2v—Mo2—Mo1iii110.082 (13)Na1—Na2—Na2xx180.000 (2)
Mo2iv—Mo2—Mo1iii144.903 (10)S1i—Na2—Na2xx77.4 (9)
Mo2iii—Mo2—Mo1iii59.650 (8)S1xvii—Na2—Na2xx77.4 (9)
Mo2i—Mo2—Mo1iii88.804 (7)S1xvi—Na2—Na2xx77.4 (9)
Mo1—Mo2—Mo1iii57.157 (12)Na1—Na2—Na1xiii0.000 (1)
Mo2—S1—Mo1iii68.80 (2)S1i—Na2—Na1xiii102.6 (9)
Mo2—S1—Mo166.67 (2)S1xvii—Na2—Na1xiii102.6 (9)
Mo1iii—S1—Mo164.26 (2)S1xvi—Na2—Na1xiii102.6 (9)
Mo2—S1—Mo1ii136.36 (4)Na2xx—Na2—Na1xiii180.000 (1)
Symmetry codes: (i) x+y+1, x+1, z; (ii) x+1, y, z; (iii) y+1, xy, z; (iv) x+y+1, y, z+1/2; (v) y+1, x+1, z+1/2; (vi) x+1, y, z; (vii) y+1, x+1, z1/2; (viii) y+1, x+y+1, z; (ix) xy, y, z1/2; (x) y+1, x, z1/2; (xi) x+1, x+y+1, z1/2; (xii) xy, x, z; (xiii) y, x, z+1/2; (xiv) x+y, x, z; (xv) y, xy, z; (xvi) y, xy1, z; (xvii) x1, y, z; (xviii) x, xy, z+1/2; (xix) x+y, y, z+1/2; (xx) x, y, z.
Selected bond lengths (Å) top
Mo1—S32.3855 (10)Mo2—Mo2v2.6440 (5)
Mo1—S1i2.4620 (8)Mo2—Mo2iv2.6745 (5)
Mo1—S12.4822 (8)Mo2—Mo2i2.6765 (4)
Mo1—S1ii2.4944 (8)K1—S32.9460 (13)
Mo1—S22.5907 (7)K1—S2vi3.4188 (7)
Mo1—Mo1iii2.6296 (5)K1—S2vii3.4188 (7)
Mo1—Mo22.7155 (4)K1—S2viii3.4188 (7)
Mo1—Mo2i2.7803 (4)Na1—S2ix3.3131 (17)
Mo2—S12.4589 (7)Na1—S1x3.856 (12)
Mo2—S22.4655 (7)Na1—S2xi3.898 (11)
Mo2—S2iii2.4904 (8)Na2—S1xii3.210 (12)
Mo2—S2iv2.5866 (7)Na2—S2xiii3.56 (2)
Symmetry codes: (i) x+y+1, x+1, z; (ii) x+1, y, z; (iii) y+1, xy, z; (iv) x+y+1, y, z+1/2; (v) y+1, x+1, z+1/2; (vi) y+1, x+y+1, z; (vii) x+1, x+y+1, z1/2; (viii) xy, x, z; (ix) x+y, x, z; (x) y, xy1, z; (xi) x, xy, z+1/2; (xii) x1, y, z; (xiii) y, xy, z.
Acknowledgements top

Intensity data were collected on the Nonius KappaCCD X-ray diffactometer system of the Centre de Diffractométrie de l'Université de Rennes I (www.cdifx.univ-rennes1.fr).

references
References top

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