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The novel structure-type Ag2.54Tl2Mo12Se15 (silver thallium molybdenum selenide) is built up of Mo6Sei8Sea6 and Mo9Sei11Sea6 cluster units in a 1:2 ratio, which are three-dimensionally connected to form the Mo-Se network. The Ag and Tl cations are distributed in several voids within the cluster network. Three of the seven independent Se atoms and one Tl atom lie on sites with 3.. symmetry (Wyckoff sites 2c or 2d).

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270110018536/fn3050sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270110018536/fn3050Isup2.hkl
Contains datablock I

Comment top

In solid-state chemistry, the crystal structures of reduced molybdenum chalcogenides are characterized by molybdenum clusters of various sizes and geometries. Although most Mo cluster compounds contain just one type of cluster, some of them can present up to four different types, as observed in Pr4Mo9O18 (Tortelier & Gougeon, 1998). In most reduced Mo chalcogenides, we have observed only one type of cluster, as exemplified by the series Mn-2Mo3nX3n+2 (M = Rb or Cs; X = S, Se or Te; n = 3, 4, 5, 6, 7, 8, 10 and 12) containing Mo9, Mo12, Mo15, Mo18, Mo21, Mo24, Mo30 and Mo36 clusters (Gautier et al., 1998; Gougeon, 1984; Gougeon et al., 1984, 1987, 1988, 1989a,b, 1990; Thomas et al., 1997; Picard, Gougeon & Potel, 1999; Picard, Halet et al., 1999). On the other hand, in the series Rb2nMo9X11Mo6nX6n+2 (n = 1, 2, 3, 4 and 5; Picard et al., 2000), we found clusters of odd and even nuclearity which coexist in equal proportions. Subsequently, we presented a new structural type, Rb4Mo21Se24 (Picard et al., 2001), also containing odd and even nuclearity clusters, i.e. Mo12 and Mo15, but in the ratio 1:2. We report here a new structural type, Ag2.54Tl2Mo12Se15, containing Mo6 and Mo9 clusters in the ratio 1:2.

A view of the crystal structure of Ag2.54Tl2Mo12Se15 is shown in Fig. 1. It is based on octahedral Mo6 and dioctahedral Mo9 clusters surrounded by 14 and 17 Se atoms, respectively (Fig. 2), to form Mo6Sei8Sea6 and Mo9Sei11Sea6 cluster units. The latter units share some of their Se ligands according to the connective formulae Mo6Sei2Sei-a6/2Sea-i6/2 and Mo9Sei5Sei-a6/2Sea-i6/2 to form the three-dimensional Mo–Se framework [for details of the i- and a-type ligand notation, see Schäfer & von Schnering (1964)]. This arrangement results in each Mo6Se8Se6 unit being surrounded by six Mo9Se11Se6 units centred at the apices of a trigonal prism, while each Mo9Se11Se6 unit is surrounded by three Mo6Se8Se6 and three Mo9Se11Se6 units, also forming a trigonal prism.

The Mo6 cluster exhibits 3.. symmetry, as in the rhombohedral Chevrel phase MxMo6Se8. The Mo6 cluster is slightly distorted, with Mo—Mo distances of 2.6879 (10) Å for the intra-triangle distances (distances between the Mo atoms related through the threefold axis) and 2.7007 (8) Å for the inter-triangle distances. This clearly indicates that the number of electrons per Mo6, also called the metallic electron count (MEC), should be close to 23. Indeed, previous work on the Chevrel phases (Yvon et al., 1977) has shown that when the MEC increases from 20 to 24, the Mo6 cluster becomes more regular. Thus, in Mo6Se8 in which the MEC is 20, the intra- and inter-triangle Mo—Mo distances are 2.683 and 2.836 (8) Å, respectively (Bars et al., 1973), while in Pr0.86Mo6Se8 (Le Berre et al., 2000), with an MEC of 22.58, the intra- and inter-triangle Mo—Mo distances are 2.6812 (6) and 2.7268 (7) Å, respectively, and in Li3.2Mo6Se8, with an MEC of 23.2, they are 2.6727 and 2.6733 Å, respectively (Cava et al., 1984).

The Mo9 cluster exhibits 3.. symmetry. The Mo—Mo distances within the Mo9 clusters are 2.6374 (8), 2.7346 (7) and 2.6163 (9) Å within the triangles made by atoms Mo2, Mo3 and Mo4, respectively, 2.6896 (8) and 2.7757 (7) Å for those between the triangles formed by atoms Mo2 and Mo3, respectively, and 2.6628 (8) and 2.7475 (8) Å for those between the triangles formed by atoms Mo3 and Mo4, respectively.

In the Mo9 cluster, the MEC, which can vary from 32 to 36 (Hughbanks & Hoffmann, 1983; Gautier et al., 1997), affects predominantly the Mo—Mo bonds within the median triangle (Mo3—Mo3 bonds in the title compound) (Potel et al., 1984). A comparison of the Mo—Mo bonds within the median triangle in different compounds containing only Mo9 clusters shows they are similar in the title compound [2.7346 (7) Å] and in Ag4.1ClMo9Se11 [2.7362 (5) Å], in which the MEC is 35.1 (Gougeon et al., 2004). Consequently, the approximately nine electrons brought by the five silver and four Tl atoms are distributed uniformly over the Mo6 and the two Mo9 clusters contained in the unit cell (about three electrons on each cluster). The average Mo—Mo distances in the two clusters are very similar, 2.693 Å in the Mo6 cluster and 2.694 Å in the Mo9 one. The shortest intercluster Mo—Mo distances are 3.604 (1) Å between the Mo6 and Mo9 clusters, and 3.6725 (9) Å between the Mo9 clusters. The Se atoms bridge either one or two Mo triangular faces of the clusters. Moreover, atoms Se1 and Se2 are linked to an Mo atom of a neighbouring cluster. The Mo—Se bond distances range from 2.5492 (9) to 2.6457 (11) Å within the Mo6Se8Se6 unit and from 2.5319 (9) to 2.7085 (10) Å within the Mo9Se11Se6 unit.

The Ag and Tl atoms reside in cavities between the cluster units. Atom Ag1 partially occupies [0.845 (3)] triangular groups of distorted tetrahedral sites of Se atoms having the apex atom Se7 in common around the threefold axis (Fig. 3). The maximum of the Ag1 probability density function is very close to the triangular face opposite the common apex atom Se7, with Ag1—Se distances of 2.577 (2), 2.6675 (17) and 2.6834 (16) Å, the Ag1—Se7 distance being 3.0215 (17) Å. The Tl1 and Tl2 cations are in a penta- and tetra-capped trigonal prismatic environment of Se atoms (Fig. 4); the former is similar to that observed for the M element in the ternary compounds M2Mo15Se19 (M = In and Ba), in which Mo6 and Mo9 clusters coexist in equal proportions (Potel et al., 1981; Gougeon et al., 1989c). The Tl—Se distances range from 3.0677 (14) to 4.2039 (10) Å for the Tl1 site.

It is interesting to note that, while in Ba2Mo15Se19 the Ba atom is nearly equidistant from the axial atoms Se6 and Se7 [3.4689 (5) and 3.4761 (5) Å, respectively], in Ag2.54Tl2Mo12Se15 atom Tl1 is displaced towards the axial atoms Se7, with a Tl1—Se6 distance of 3.0677 (14) Å compared with 3.8863 (14) Å for Tl1—Se7. This effect, which may result from the lone pair, is also observed to a lesser extent in In2Mo15Se19, with In—Se distances of 3.468 (6) and 3.593 (6) Å. The environment of atom Tl2 has previously been observed in Tl2Mo9S11 (Potel et al., 1980), in which Mo6 and Mo12 clusters are found, as well as in Cr1.45Tl1.87Mo15Se19, containing an equal mixture of Mo6 and Mo9 clusters (Gougeon et al., 2009). In the latter compound, the Tl—Se distances range from 3.1152 (11) to 4.2214 (9) Å, compared with 2.9991 (15) to 4.0667 (10) Å in the title compound. The average Tl—Se values of 3.67 and 3.68 Å for the Tl1 and Tl2 sites, respectively, are in very good agreement with the distance of 3.68 Å expected from the sum of the ionic radii of Se2- and Tl+ with coordination number 12, according to Shannon (1976).

In Rb2n(Mo9S11)(Mo6nS6n+2) compounds, extended Hückel tight-binding (EH—TB) calculations have shown that the clusters are hypoelectronic (Picard et al., 2000). Assuming a +1 oxidation state for the Ag and Tl cations, the MEC of the whole molybdenum cluster in the title compound is 46.5. Because there are twice as many Mo9 as Mo6 in this compound, the MEC of one Mo6 and two Mo9 units is 93. EH—TB calculations have been carried out in order to check the assumption, based on distance analysis, that electrons provided by Ag and Tl cations are uniformly distributed over both clusters. The electronic structure of the title compound is approximated by (Mo12Se15)4.5-. The molybdenum and selenium extended Hückel parameters used by Gautier et al. (1998) have been considered. The total and Mo projected density of states (DOS) curves obtained from 32 irreducible k points are sketched in Fig. 5. The Fermi level cuts a narrow peak of DOS centred on the Mo6 cluster. This peak is derived mainly from the doubly degenerate eg level of the molecular orbital diagram of an isolated Mo6Se14 cluster (Hughbanks & Hoffmann, 1983). Since this peak is roughly half-occupied, the MEC of the Mo6 unit is close to 22 ME. The two DOS peaks that lie above the Fermi level are derived mainly from the Mo9 cluster. These peaks show some Mo—Mo antibonding character within the bioctahedral cluster, whereas the occupied bands show an overall Mo—Mo character within the same cluster. This means that the MEC of the Mo9 unit in this compound must be close to the optimal value. In fact, assuming an MEC of 22 for the Mo6 cluster, the MEC per Mo9 unit is (93 - 22)/2 = 35.5. This distribution differs slightly from that resulting from the analysis of Mo—Mo distances within the clusters. However, this difference cannot be considered significant since: (i) the quantum periodic calculations we have carried out are semi-empirical, (ii) Ag and Tl atoms have been neglected within the calculations because of the lack of reliable EH paramaters for Tl, and (iii) the MEC values resulting from the empirical distance analysis show significant uncertainties.

Related literature top

For related literature, see: Altomare et al. (1999); Bachmann & Schulz (1984); Bars et al. (1973); Cava et al. (1984); Gautier et al. (1997, 1998); Gougeon (1984); Gougeon et al. (1987, 1988, 1989a, 1989b, 1989c, 1990, 2004, 2009); Gougeon, Padiou, Le Marouille, Potel & Sergent (1984); Hughbanks & Hoffmann (1983); Johnson & Levy (1974); Le Berre, Hamard, Pena & Wojakowski (2000); Picard et al. (2000, 2001); Picard, Gougeon & Potel (1999); Picard, Halet, Gougeon & Potel (1999); Potel et al. (1980, 1981, 1984); Schäfer & von Schnering (1964); Shannon (1976); Spek (2009); Thomas et al. (1997); Tortelier & Gougeon (1998); Yvon et al. (1977).

Experimental top

Single crystals of Ag2.54Tl2Mo12Se15 were prepared from a mixture of Ag, MoSe2, TlSe and Mo with the nominal composition Ag4Tl2Mo12Se14. Before use, Mo powder was reduced under H2 flowing gas at 1273 K for 10 h in order to eliminate any trace of oxygen. The binaries MoSe2 and TlSe were obtained by heating stoichiometric mixtures of the elements in sealed evacuated silica tubes for about 2 d at 1073 and 573 K, respectively. All handling of materials was carried out in an argon-filled glove box. 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 a rate of 300 K h-1 up to 1523 K, held at that temperature for 48 h, cooled at 100 K h-1 to 1373 K, and finally furnace cooled. [Crystals retrieved, washed? Other products formed?]

Refinement top

The structure was solved in space group P3 using SIR97 (Altomare et al., 1999), which revealed all atoms. The final model was refined down to R = 0.169. Analysis of the data with the TwinRotMat procedure implemented in PLATON (Spek, 2009) revealed that the crystal investigated was merohedrally twinned. Introduction of the twinning matrix (010, 100, 001) lowered the R factor to 0.059. A t this stage, the difference Fourier map revealed significant electron densities near the atoms Tl1 (5.10 and -2.45 e Å-3), Tl2 (7.75 and -8.06 e Å-3) and Ag1 (5.59 and -3.85 e Å-3). Fourth-order tensors in the Gram–Charlier expansion (Johnson & Levy, 1974) of the thallium and silver displacement parameters were used to better describe the electronic density around these cationic sites. The residual R value dropped to 0.0476 and the residual peaks in the vicinity of Tl1 to 3.50 and -1.64 e Å-3, Tl2 to 2.87 and -1.72 e Å-3 and Ag1 to 2.05 and -1.95 e Å-3. The non-harmonic probability density function maps of Tl1, Tl2 and Ag1 did not show significant negative regions, indicating that the refined model can be considered valid (Bachmann & Schulz, 1984). Fig. 6 shows the isosurfaces of the probability density for the Ag and Tl atoms. The twin volume ratio was refined to 0.338 (1):0.662 (1). Refinement of the occupancy factor of atom Ag1 led to the final stoichiometry Ag2.535 (9)Tl2Mo12Se15.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: COLLECT (Nonius, 1998); data reduction: EVALCCD (Duisenberg, 1998); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: JANA2006 (Petříček et al., 2006).

Figures top
[Figure 1] Fig. 1. A view of Ag2.54Tl2Mo12Se15, along [110]. Displacement ellipsoids are drawn at the 97% probability level.
[Figure 2] Fig. 2. Plot showing the atom-numbering scheme and the interunit linkage of the Mo9Se11Se6 and Mo6Se8Se6 cluster units. Displacement ellipsoids are drawn at the 97% probability level.
[Figure 3] Fig. 3. Se coordination polyhedra for Ag1. [Please define symmetry codes (i) and (v)]
[Figure 4] Fig. 4. The environments of atoms Tl1 and Tl2. [Please define symmetry codes (viii), (ix), (x), (xi), (xii) and (xiii)]
[Figure 5] Fig. 5. Total density of states computed for Mo12Se154.5-, and projected contributions arising from Mo6 and Mo9 clusters.
[Figure 6] Fig. 6. Nonharmonic probability density isosurfaces, viewed along the c axis, for (a) Tl1, (b) Tl2 and (c) Ag1. Se atoms are drawn at an arbitrary size. The level of the three-dimensional maps is 0.05 Å-3.
silver thallium molybdenum selenide top
Crystal data top
Ag2.535Mo12Se15Tl2Dx = 7.452 Mg m3
Mr = 3017.9Mo Kα radiation, λ = 0.71069 Å
Trigonal, P3Cell parameters from 24586 reflections
Hall symbol: -P 3θ = 1.0–40.3°
a = 9.9962 (1) ŵ = 39.41 mm1
c = 15.5364 (3) ÅT = 293 K
V = 1344.47 (3) Å3Irregular block, black
Z = 20.07 × 0.06 × 0.03 mm
F(000) = 2590
Data collection top
Nonius KappaCCD area-detector
diffractometer
5641 independent reflections
Radiation source: fine-focus sealed tube4029 reflections with I > 2σ(I)
Horizontally mounted graphite crystal monochromatorRint = 0.097
Detector resolution: 9 pixels mm-1θmax = 40.3°, θmin = 1.3°
CCD scansh = 1718
Absorption correction: analytical
(de Meulenaer & Tompa, 1965)
k = 1815
Tmin = 0.104, Tmax = 0.346l = 2628
31332 measured reflections
Refinement top
Refinement on F20 constraints
R[F2 > 2σ(F2)] = 0.048Weighting scheme based on measured s.u.'s w = 1/[σ2(I) + 0.0001I2]
wR(F2) = 0.079(Δ/σ)max = 0.025
S = 1.28Δρmax = 3.78 e Å3
5641 reflectionsΔρmin = 2.71 e Å3
143 parametersExtinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 restraintsExtinction coefficient: 340 (30)
Crystal data top
Ag2.535Mo12Se15Tl2Z = 2
Mr = 3017.9Mo Kα radiation
Trigonal, P3µ = 39.41 mm1
a = 9.9962 (1) ÅT = 293 K
c = 15.5364 (3) Å0.07 × 0.06 × 0.03 mm
V = 1344.47 (3) Å3
Data collection top
Nonius KappaCCD area-detector
diffractometer
5641 independent reflections
Absorption correction: analytical
(de Meulenaer & Tompa, 1965)
4029 reflections with I > 2σ(I)
Tmin = 0.104, Tmax = 0.346Rint = 0.097
31332 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.048143 parameters
wR(F2) = 0.0790 restraints
S = 1.28Δρmax = 3.78 e Å3
5641 reflectionsΔρmin = 2.71 e Å3
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Mo10.14729 (6)0.01484 (6)0.42887 (3)0.01044 (18)
Mo20.32300 (6)0.50944 (6)0.33467 (3)0.01018 (18)
Mo30.17519 (6)0.50893 (6)0.18991 (3)0.00931 (17)
Mo40.34263 (6)0.52042 (6)0.04704 (3)0.00974 (18)
Se10.31539 (7)0.28354 (7)0.43443 (4)0.0128 (2)
Se20.01788 (7)0.38011 (7)0.33089 (4)0.0133 (2)
Se30.33177 (8)0.36803 (7)0.19112 (4)0.0129 (2)
Se40.04697 (7)0.35078 (7)0.04759 (4)0.0132 (2)
Se5000.29869 (6)0.0163 (3)
Se60.3333330.6666670.46487 (6)0.0143 (2)
Se70.3333330.6666670.08754 (6)0.0142 (3)
Ag10.3734 (2)0.13368 (16)0.18730 (9)0.0514 (10)0.845 (3)
Tl10.3333330.6666670.66232 (7)0.0421 (4)
Tl2110.89434 (8)0.0740 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mo10.0110 (2)0.0105 (2)0.0092 (2)0.00483 (19)0.00043 (18)0.00029 (17)
Mo20.0108 (2)0.0107 (2)0.0093 (2)0.00547 (19)0.00035 (17)0.00016 (17)
Mo30.0096 (2)0.0092 (2)0.0090 (2)0.00457 (16)0.00012 (17)0.00035 (17)
Mo40.0103 (2)0.0099 (2)0.0094 (2)0.00523 (19)0.00000 (17)0.00068 (17)
Se10.0124 (3)0.0111 (3)0.0134 (3)0.0048 (2)0.0015 (2)0.0027 (2)
Se20.0128 (3)0.0119 (3)0.0139 (3)0.0052 (2)0.0012 (2)0.0031 (2)
Se30.0162 (3)0.0113 (3)0.0131 (3)0.0084 (3)0.00083 (19)0.0004 (2)
Se40.0125 (3)0.0127 (3)0.0132 (3)0.0053 (2)0.0025 (2)0.0008 (2)
Se50.0192 (3)0.0192 (3)0.0105 (4)0.00960 (16)00
Se60.0167 (3)0.0167 (3)0.0095 (4)0.00836 (16)00
Se70.0162 (3)0.0162 (3)0.0102 (4)0.00812 (16)00
Ag10.1163 (17)0.0364 (9)0.0277 (8)0.0577 (11)0.0151 (9)0.0077 (6)
Tl10.0470 (5)0.0470 (5)0.0322 (6)0.0235 (3)00
Tl20.0967 (9)0.0967 (9)0.0287 (7)0.0483 (4)00
Geometric parameters (Å, º) top
Mo1—Mo1i2.6879 (12)Mo4—Se4v2.6637 (8)
Mo1—Mo1ii2.6879 (10)Mo4—Se4viii2.6520 (12)
Mo1—Mo1iii2.7007 (7)Mo4—Se72.5795 (9)
Mo1—Mo1iv2.7007 (8)Tl2—Tl2ix3.2831 (17)
Mo1—Mo2ii3.6041 (10)Ag1—Se2ii2.6675 (17)
Mo1—Se12.5914 (8)Ag1—Se32.577 (2)
Mo1—Se1ii2.6193 (8)Ag1—Se4ii2.6834 (16)
Mo1—Se1iii2.5741 (9)Ag1—Se7vii3.0215 (17)
Mo1—Se2ii2.6457 (11)Tl1—Se1x3.6179 (9)
Mo1—Se52.5492 (9)Tl1—Se1xi3.6179 (11)
Mo2—Mo2v2.6374 (8)Tl1—Se1iv3.6179 (8)
Mo2—Mo32.6896 (8)Tl1—Se2xii3.3036 (8)
Mo2—Mo3v2.7757 (7)Tl1—Se2iii3.3036 (11)
Mo2—Se12.7085 (10)Tl1—Se2xiii3.3036 (6)
Mo2—Se22.6523 (8)Tl1—Se3x4.2039 (10)
Mo2—Se2v2.5787 (8)Tl1—Se3xi4.2039 (11)
Mo2—Se32.6652 (9)Tl1—Se3iv4.2039 (9)
Mo2—Se62.5319 (9)Tl1—Se63.0677 (14)
Mo3—Mo3v2.7346 (7)Tl1—Se7xiv3.8863 (14)
Mo3—Mo42.7475 (8)Tl2—Se3xv3.7544 (7)
Mo3—Mo4vi2.6628 (8)Tl2—Se3xvi3.7544 (9)
Mo3—Se22.6275 (7)Tl2—Se3xvii3.7544 (10)
Mo3—Se32.5765 (11)Tl2—Se4xv3.4181 (8)
Mo3—Se3vi2.5839 (13)Tl2—Se4xvi3.4181 (7)
Mo3—Se42.6466 (8)Tl2—Se4xvii3.4181 (11)
Mo4—Mo4v2.6163 (9)Tl2—Se4xviii4.0667 (10)
Mo4—Mo4vii3.6725 (9)Tl2—Se4xix4.0667 (9)
Mo4—Se32.6791 (9)Tl2—Se4xx4.0667 (12)
Mo4—Se42.5688 (8)Tl2—Se5xv2.9991 (15)
Mo1i—Mo1—Mo1ii60.00 (2)Mo2—Mo3—Mo4110.66 (3)
Mo1i—Mo1—Mo1iii90Mo2vi—Mo3—Mo3v88.06 (2)
Mo1i—Mo1—Mo1iv60.16 (3)Mo2vi—Mo3—Mo3vi58.427 (18)
Mo1ii—Mo1—Mo1iii60.16 (2)Mo3v—Mo3—Mo3vi60.00 (3)
Mo1ii—Mo1—Mo1iv90Mo3v—Mo3—Mo458.119 (18)
Mo1iii—Mo1—Mo1iv59.69 (2)Mo3v—Mo3—Mo4vi89.59 (2)
Mo2v—Mo2—Mo2vi60.00 (2)Mo3vi—Mo3—Mo487.85 (2)
Mo2v—Mo2—Mo391.94 (2)Mo3vi—Mo3—Mo4vi61.183 (19)
Mo2v—Mo2—Mo3v59.52 (2)Mo4—Mo3—Mo4vi57.81 (2)
Mo2vi—Mo2—Mo362.80 (2)Mo3—Mo4—Mo3v60.698 (18)
Mo2vi—Mo2—Mo3v90.04 (3)Mo3—Mo4—Mo4v90.28 (2)
Mo3—Mo2—Mo3v60.022 (18)Mo3—Mo4—Mo4vi59.47 (2)
Mo2—Mo3—Mo2vi57.68 (2)Mo3v—Mo4—Mo4v62.72 (2)
Mo2—Mo3—Mo3v61.552 (19)Mo3v—Mo4—Mo4vi92.17 (3)
Mo2—Mo3—Mo3vi89.84 (2)Mo4v—Mo4—Mo4vi60.00 (2)
Symmetry codes: (i) y, xy, z; (ii) x+y, x, z; (iii) y, x+y, z1; (iv) xy, x, z1; (v) y1, xy1, z; (vi) x+y, x1, z; (vii) x1, y1, z; (viii) y, x+y, z; (ix) x+2, y+2, z+2; (x) x1, y1, z1; (xi) y, x+y1, z1; (xii) x, y1, z1; (xiii) xy1, x1, z1; (xiv) x, y, z1; (xv) x+1, y+1, z+1; (xvi) y+1, xy+1, z+1; (xvii) x+y+1, x+1, z+1; (xviii) x+1, y+1, z+1; (xix) y+1, x+y+1, z+1; (xx) xy+1, x+1, z+1.

Experimental details

Crystal data
Chemical formulaAg2.535Mo12Se15Tl2
Mr3017.9
Crystal system, space groupTrigonal, P3
Temperature (K)293
a, c (Å)9.9962 (1), 15.5364 (3)
V3)1344.47 (3)
Z2
Radiation typeMo Kα
µ (mm1)39.41
Crystal size (mm)0.07 × 0.06 × 0.03
Data collection
DiffractometerNonius KappaCCD area-detector
diffractometer
Absorption correctionAnalytical
(de Meulenaer & Tompa, 1965)
Tmin, Tmax0.104, 0.346
No. of measured, independent and
observed [I > 2σ(I)] reflections
31332, 5641, 4029
Rint0.097
(sin θ/λ)max1)0.909
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.079, 1.28
No. of reflections5641
No. of parameters143
Δρmax, Δρmin (e Å3)3.78, 2.71

Computer programs: COLLECT (Nonius, 1998), EVALCCD (Duisenberg, 1998), SIR97 (Altomare et al., 1999), JANA2006 (Petříček et al., 2006), DIAMOND (Brandenburg, 2001).

Selected bond lengths (Å) top
Mo1—Mo1i2.6879 (10)Mo3—Se42.6466 (8)
Mo1—Mo1ii2.7007 (7)Mo4—Mo4iii2.6163 (9)
Mo1—Mo2i3.6041 (10)Mo4—Mo4v3.6725 (9)
Mo1—Se12.5914 (8)Mo4—Se32.6791 (9)
Mo1—Se1i2.6193 (8)Mo4—Se42.5688 (8)
Mo1—Se1ii2.5741 (9)Mo4—Se4iii2.6637 (8)
Mo1—Se2i2.6457 (11)Mo4—Se4vi2.6520 (12)
Mo1—Se52.5492 (9)Mo4—Se72.5795 (9)
Mo2—Mo2iii2.6374 (8)Tl2—Tl2vii3.2831 (17)
Mo2—Mo32.6896 (8)Ag1—Se2i2.6675 (17)
Mo2—Mo3iii2.7757 (7)Ag1—Se32.577 (2)
Mo2—Se12.7085 (10)Ag1—Se4i2.6834 (16)
Mo2—Se22.6523 (8)Ag1—Se7v3.0215 (17)
Mo2—Se2iii2.5787 (8)Tl1—Se1viii3.6179 (8)
Mo2—Se32.6652 (9)Tl1—Se2ix3.3036 (8)
Mo2—Se62.5319 (9)Tl1—Se3viii4.2039 (9)
Mo3—Mo3iii2.7346 (7)Tl1—Se63.0677 (14)
Mo3—Mo42.7475 (8)Tl1—Se7x3.8863 (14)
Mo3—Mo4iv2.6628 (8)Tl2—Se3xi3.7544 (7)
Mo3—Se22.6275 (7)Tl2—Se4xii3.4181 (7)
Mo3—Se32.5765 (11)Tl2—Se4xiii4.0667 (9)
Mo3—Se3iv2.5839 (13)Tl2—Se5xi2.9991 (15)
Symmetry codes: (i) x+y, x, z; (ii) y, x+y, z1; (iii) y1, xy1, z; (iv) x+y, x1, z; (v) x1, y1, z; (vi) y, x+y, z; (vii) x+2, y+2, z+2; (viii) xy, x, z1; (ix) x, y1, z1; (x) x, y, z1; (xi) x+1, y+1, z+1; (xii) y+1, xy+1, z+1; (xiii) y+1, x+y+1, z+1.
 

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