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A new monoclinic polymorph, β-K4Ge4Se10 (tetra­potassium deca­selenidotetra­germanate), that crystallizes in space group P21/c has been isolated. The structure contains isolated super-tetra­hedral adamantane [Ge4Se10]4− clusters identical to those in the known K4Ge4Se10 polymorph (P21/m), held together in in the crystal structure by ionic inter­action with the K+ ions. The adamantane unit, [Ge4Se10]4−, is formed by corner-sharing of four GeSe4 tetra­hedra, with average Ge—Se distances of 2.378 and 2.281 Å for (Ge—Se)endo and (Ge—Se)exo, respectively. There are four crystallographically distinct K+ ions in β-K4Ge4Se10 having coordination numbers of 5, 7 and 8 (× 2), with K—Se distances in the range 2.986 (2)–3.888 (1) Å, while the coordination numbers of the three unique K+ ions in the known K4Ge4Se10 (P21/m) vary between 5 and 7. Besides the differences in coordination numbers of K+ ions, the two polymorphs also exhibit a different packing of the adamantane units.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807023264/wm2110sup1.cif
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807023264/wm2110Isup2.hkl
Contains datablock I

Key indicators

  • Single-crystal X-ray study
  • T = 100 K
  • Mean [sigma](e-Ge) = 0.001 Å
  • R factor = 0.041
  • wR factor = 0.103
  • Data-to-parameter ratio = 29.4

checkCIF/PLATON results

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Alert level C PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ? PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.68
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 2 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

The structure determination of K4Ge4Se10 was first carried out by Eisenmann and Hansa (1993). The compound was synthesized by stoichiometric combination of elements in an evacuated graphitized silica ampoule at 1073 K. It crystallizes in space group P21/m with cell parameters a = 10.202 (6) Å, b = 11.544 (6) Å, c = 9.806 (6) Å, β = 90.6 (1)°, V = 1154.8 Å3. Wachhold & Kanatzidis (2000) reported the synthesis of K4Ge4Se10 starting with K2Se, Ge and Se, following the same route by which we have synthesized K4Ge4Se10 and determined its crystal structure at 100 K, which reveals that the cell pararmeters are different from those reported by Eisenmann and Hansa (1993). The present β-structure crystallizes in the monoclinic system but with a different space group (P21/c); although there is an obvious metric relationship between the unit cells of the two structures, their symmetries do not allow to transform one structure into another.

Complementary views of the two polymorphs are given in Fig. 1. The structure of β-K4Ge4Se10 contains isolated adamantane-like [Ge4Se10]4- units formed by four corner-shared GeSe4 tetrahedra similar to K4Ge4Se10P21/m. However, these units are arranged differently in the two polymorphs. In both the structures, anionic adamantane units are stacked one over the other along the c- and b axis for K4Ge4Se10P21/m and β-K4Ge4Se10, respectively, held together by K+ cations to form a column. Such columns are placed side by side in a layer like arrangement parallel to the ac- and ab-plane, for K4Ge4Se10P21/m and β-K4Ge4Se10, respectively. In K4Ge4Se10P21/m the adamantane units are arranged such that [Ge4Se10]4- super tetrahedra are face up in one layer while they are placed face down in the next layer, which means the Se atoms are arranged in opposite directions in alternate layer. However, in the new polymorph, β-K4Ge4Se10, the directions of the super tetrahedra (arrangement of Se atoms) alternate in every two layers (Fig. 1). Thus in β-K4Ge4Se10 the c axis is approximately doubled the length of the b axis in K4Ge4Se10P21/m. The average Ge—Se distances (d(Ge—Se)endo = 2.378, d(Ge—Se)exo = 2.281 Å; Table 1) and the coordination number of the K+ ions (CN = 5–8) of β-K4Ge4Se10 are comparable to that of K4Ge4Se10P21/m.

Related literature top

For the first polymorph (P21/m) of this composition, see: Eisenmann & Hansa (1993); for preparation, see: Wachhold & Kanatzidis (2000); Wachhold et al. (2000).

Experimental top

The synthesis of β-K4Ge4Se10 was carried out according to the reported procedure (Wachhold and Kanatzidis, 2000) but with a longer heating time, 48 hrs compared to 32 hrs. Orange needles of K4Ge4Se10 were obtained from a solid-state reaction of K2Se, Ge, and Se by mixing stoichiometric amounts (1:2:4) of 471.46 mg K2Se (prepared following the reported procedure, Wachhold and Kanatzidis, 2000), 435.6 mg Ge (Cerac, 99.999%), and 947.5 mg of Se (Aldrich, 99.5%). The reactants were loaded into a fused-silica tube under N2 atmosphere in a glovebox. The tube was torch-sealed under vacuum and then placed in a furnace. The sample was heated to 1123 K at a rate of 35 K/h, held at 1123 k for 48 h, and then cooled to room temperature at a cooling rate of 35 K/h. The tube was opened under N2, the product was ground and powder X-ray diffraction (PXRD) was carried out. The PXRD did not match with the simulated pattern from the atomic coordinates of known K4Ge4Se10 (P21/m) (Eisenmann and Hansa, 1993). This led us to believe that the current product could be a polymorphic modification and subsequent single-crystal X-ray data revealed different cell parameters and structure solution indicated a new polymorph of K4Ge4Se10 (in P21/c space group, β-phase). The experimental PXRD was in good agreement with the simulated pattern of β-K4Ge4Se10. The finely ground product was air sensitive and decomposed after 20–30 minutes of exposure in air. The single-crystal X-ray data was collected at low temperature (100 K) under a flow of liquid N2 and the crystal did not show any sign of decomposition during the period of data collection. Although β-K4Ge4Se10 was obtained following the reported synthesis procedure (Wachhold and Kanatzidis, 2000; Wachhold et al., 2000), however, they did not report a detailed crystallographic characterization of their K4Ge4Se10 and hence it is unclear whether they also obtained the same polymorph as reported here.

Refinement top

The highest peak and the deepest hole in the final Fourier map are 0.96 Å from Ge4 and 2.16 Å from Se10, respectively.

Structure description top

The structure determination of K4Ge4Se10 was first carried out by Eisenmann and Hansa (1993). The compound was synthesized by stoichiometric combination of elements in an evacuated graphitized silica ampoule at 1073 K. It crystallizes in space group P21/m with cell parameters a = 10.202 (6) Å, b = 11.544 (6) Å, c = 9.806 (6) Å, β = 90.6 (1)°, V = 1154.8 Å3. Wachhold & Kanatzidis (2000) reported the synthesis of K4Ge4Se10 starting with K2Se, Ge and Se, following the same route by which we have synthesized K4Ge4Se10 and determined its crystal structure at 100 K, which reveals that the cell pararmeters are different from those reported by Eisenmann and Hansa (1993). The present β-structure crystallizes in the monoclinic system but with a different space group (P21/c); although there is an obvious metric relationship between the unit cells of the two structures, their symmetries do not allow to transform one structure into another.

Complementary views of the two polymorphs are given in Fig. 1. The structure of β-K4Ge4Se10 contains isolated adamantane-like [Ge4Se10]4- units formed by four corner-shared GeSe4 tetrahedra similar to K4Ge4Se10P21/m. However, these units are arranged differently in the two polymorphs. In both the structures, anionic adamantane units are stacked one over the other along the c- and b axis for K4Ge4Se10P21/m and β-K4Ge4Se10, respectively, held together by K+ cations to form a column. Such columns are placed side by side in a layer like arrangement parallel to the ac- and ab-plane, for K4Ge4Se10P21/m and β-K4Ge4Se10, respectively. In K4Ge4Se10P21/m the adamantane units are arranged such that [Ge4Se10]4- super tetrahedra are face up in one layer while they are placed face down in the next layer, which means the Se atoms are arranged in opposite directions in alternate layer. However, in the new polymorph, β-K4Ge4Se10, the directions of the super tetrahedra (arrangement of Se atoms) alternate in every two layers (Fig. 1). Thus in β-K4Ge4Se10 the c axis is approximately doubled the length of the b axis in K4Ge4Se10P21/m. The average Ge—Se distances (d(Ge—Se)endo = 2.378, d(Ge—Se)exo = 2.281 Å; Table 1) and the coordination number of the K+ ions (CN = 5–8) of β-K4Ge4Se10 are comparable to that of K4Ge4Se10P21/m.

For the first polymorph (P21/m) of this composition, see: Eisenmann & Hansa (1993); for preparation, see: Wachhold & Kanatzidis (2000); Wachhold et al. (2000).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. Ball and stick representation of the packing of adamantane units in the two polymorphs: K4Ge4Se10P21/m (left), β-K4Ge4Se10 (right).
tetrapotassium decaselenidotetragermanate top
Crystal data top
K4Ge4Se10F(000) = 2176
Mr = 1236.36Dx = 3.669 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 5478 reflections
a = 9.9796 (8) Åθ = 2.3–28.3°
b = 9.7047 (8) ŵ = 22.31 mm1
c = 23.184 (2) ÅT = 100 K
β = 94.508 (2)°Irregular, orange
V = 2238.4 (3) Å30.26 × 0.12 × 0.06 mm
Z = 4
Data collection top
Bruker SMART CCD area detector
diffractometer
4823 independent reflections
Radiation source: fine-focus sealed tube3896 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.069
φ and ω scansθmax = 27.0°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 1212
Tmin = 0.054, Tmax = 0.262k = 1212
19344 measured reflectionsl = 2929
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)] = 0.042 w = 1/[σ2(Fo2) + (0.0511P)2 + 6.4498P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.103(Δ/σ)max < 0.001
S = 1.04Δρmax = 1.72 e Å3
4823 reflectionsΔρmin = 1.47 e Å3
164 parametersExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.00274 (12)
Crystal data top
K4Ge4Se10V = 2238.4 (3) Å3
Mr = 1236.36Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.9796 (8) ŵ = 22.31 mm1
b = 9.7047 (8) ÅT = 100 K
c = 23.184 (2) Å0.26 × 0.12 × 0.06 mm
β = 94.508 (2)°
Data collection top
Bruker SMART CCD area detector
diffractometer
4823 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
3896 reflections with I > 2σ(I)
Tmin = 0.054, Tmax = 0.262Rint = 0.069
19344 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.042164 parameters
wR(F2) = 0.1030 restraints
S = 1.04Δρmax = 1.72 e Å3
4823 reflectionsΔρmin = 1.47 e Å3
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*/Ueq
Ge10.05608 (7)0.77088 (7)0.37483 (3)0.01313 (18)
Ge20.84125 (7)0.08752 (7)0.37930 (3)0.01123 (17)
Ge30.72783 (7)0.75584 (7)0.30709 (3)0.01103 (17)
Ge40.73792 (7)0.77065 (7)0.47074 (3)0.01166 (17)
Se10.61852 (7)0.67644 (7)0.39529 (3)0.01264 (16)
Se20.96086 (7)0.68890 (7)0.46503 (3)0.01607 (18)
Se30.27457 (7)0.70088 (7)0.36540 (3)0.01702 (18)
Se40.83817 (7)0.32038 (7)0.37588 (3)0.01580 (18)
Se50.71983 (7)0.00069 (7)0.30260 (3)0.01306 (17)
Se60.72631 (7)0.01489 (7)0.46832 (3)0.01402 (17)
Se70.95299 (7)0.67889 (7)0.29407 (3)0.01363 (17)
Se80.06604 (7)0.01348 (7)0.37121 (3)0.01835 (18)
Se90.61132 (7)0.68152 (7)0.23270 (3)0.01788 (18)
Se100.62389 (7)0.69187 (7)0.55318 (3)0.01533 (17)
K10.84052 (16)0.61928 (16)0.65528 (7)0.0223 (4)
K20.43100 (16)0.99728 (15)0.39359 (7)0.0163 (3)
K30.31801 (17)0.62238 (16)0.50104 (7)0.0221 (4)
K40.67980 (19)0.35486 (18)0.26208 (8)0.0288 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ge10.0119 (4)0.0106 (3)0.0157 (4)0.0012 (3)0.0064 (3)0.0001 (3)
Ge20.0138 (4)0.0092 (3)0.0098 (4)0.0003 (3)0.0052 (3)0.0017 (3)
Ge30.0121 (3)0.0108 (3)0.0090 (4)0.0009 (3)0.0063 (3)0.0009 (3)
Ge40.0156 (4)0.0089 (3)0.0095 (4)0.0005 (3)0.0049 (3)0.0021 (3)
Se10.0125 (3)0.0121 (3)0.0126 (4)0.0010 (3)0.0044 (3)0.0010 (3)
Se20.0167 (4)0.0141 (3)0.0159 (4)0.0015 (3)0.0083 (3)0.0043 (3)
Se30.0112 (3)0.0153 (3)0.0232 (4)0.0008 (3)0.0072 (3)0.0019 (3)
Se40.0232 (4)0.0098 (3)0.0133 (4)0.0009 (3)0.0058 (3)0.0013 (3)
Se50.0165 (4)0.0111 (3)0.0105 (3)0.0018 (3)0.0065 (3)0.0016 (3)
Se60.0233 (4)0.0092 (3)0.0092 (3)0.0015 (3)0.0013 (3)0.0009 (3)
Se70.0133 (3)0.0132 (3)0.0136 (4)0.0016 (3)0.0038 (3)0.0020 (3)
Se80.0141 (4)0.0122 (3)0.0275 (4)0.0011 (3)0.0063 (3)0.0022 (3)
Se90.0203 (4)0.0177 (4)0.0137 (4)0.0009 (3)0.0113 (3)0.0038 (3)
Se100.0239 (4)0.0116 (3)0.0101 (3)0.0014 (3)0.0017 (3)0.0020 (3)
K10.0240 (8)0.0184 (8)0.0233 (9)0.0021 (7)0.0057 (7)0.0017 (7)
K20.0188 (8)0.0150 (7)0.0143 (8)0.0010 (6)0.0045 (6)0.0027 (6)
K30.0275 (9)0.0182 (8)0.0196 (8)0.0035 (7)0.0052 (7)0.0052 (7)
K40.0406 (11)0.0204 (8)0.0220 (9)0.0030 (7)0.0190 (8)0.0049 (7)
Geometric parameters (Å, º) top
Ge1—Se7i2.2492 (10)Se8—K1v3.7468 (18)
Ge1—Se32.3105 (10)Se9—K43.3027 (19)
Ge1—Se8ii2.3583 (10)Se9—K4vi3.368 (2)
Ge1—Se2i2.4943 (11)Se9—K2x3.4284 (17)
Ge2—Se52.2366 (9)Se9—K1iv3.5827 (19)
Ge2—Se42.2613 (9)Se10—K13.1574 (17)
Ge2—Se8iii2.3769 (10)Se10—K33.2640 (18)
Ge2—Se62.5384 (10)Se10—K2xi3.3211 (17)
Ge3—Se92.1288 (9)Se10—K3v3.3663 (17)
Ge3—Se5ii2.3795 (10)K1—Se3v3.3341 (17)
Ge3—Se72.4092 (10)K1—Se4vii3.3929 (19)
Ge3—Se12.5131 (10)K1—Se9xii3.5827 (19)
Ge3—K1iv3.9678 (19)K1—Se7vii3.6904 (17)
Ge4—Se12.2335 (9)K1—Se8v3.7468 (18)
Ge4—Se6ii2.3735 (9)K1—Se7xii3.8577 (17)
Ge4—Se22.3755 (10)K1—Se5xiii3.8882 (19)
Ge4—Se102.4238 (10)K1—Ge3xii3.9678 (19)
Ge4—K3v3.9173 (18)K1—K3v4.499 (2)
Se1—K23.6314 (16)K1—K2xi4.689 (2)
Se1—K3v3.7879 (18)K1—K4vii5.021 (2)
Se2—Ge1iii2.4943 (11)K2—Se6ii3.3035 (16)
Se2—K3iii3.6537 (18)K2—Se10xi3.3211 (17)
Se3—K33.2317 (18)K2—Se9vi3.4284 (17)
Se3—K23.3133 (16)K2—Se8ii3.6418 (17)
Se3—K1v3.3341 (17)K2—Se6v3.6768 (18)
Se3—K4vi3.374 (2)K2—Se5ii3.7034 (18)
Se4—K42.9859 (17)K2—K4vi3.941 (2)
Se4—K1vii3.3929 (19)K2—K34.600 (2)
Se4—K3v3.4028 (19)K2—K1xi4.689 (2)
Se5—Ge3viii2.3795 (10)K2—K3xi4.990 (2)
Se5—K43.5773 (18)K3—Se10v3.3663 (17)
Se5—K2viii3.7034 (18)K3—Se4v3.4028 (19)
Se5—K1ix3.8882 (19)K3—Se6v3.6252 (17)
Se6—Ge4viii2.3735 (9)K3—Se2i3.6537 (18)
Se6—K2viii3.3035 (16)K3—Se1v3.7879 (18)
Se6—K3v3.6252 (17)K3—Ge4v3.9173 (18)
Se6—K2v3.6768 (18)K3—K3v4.344 (3)
Se7—Ge1iii2.2492 (10)K3—K1v4.499 (2)
Se7—K1vii3.6904 (17)K3—K2xi4.990 (2)
Se7—K1iv3.8577 (17)K4—Se9x3.368 (2)
Se8—Ge1viii2.3583 (10)K4—Se3x3.374 (2)
Se8—Ge2i2.3769 (10)K4—K2x3.941 (2)
Se8—K2viii3.6418 (17)K4—K1vii5.021 (2)
Se7i—Ge1—Se3100.24 (4)Se10—K1—K4vii148.33 (6)
Se7i—Ge1—Se8ii112.61 (4)Se3v—K1—K4vii114.13 (4)
Se3—Ge1—Se8ii104.32 (4)Se4vii—K1—K4vii35.31 (3)
Se7i—Ge1—Se2i113.08 (4)Se9xii—K1—K4vii114.14 (4)
Se3—Ge1—Se2i114.21 (4)Se7vii—K1—K4vii54.97 (3)
Se8ii—Ge1—Se2i111.60 (4)Se8v—K1—K4vii76.87 (3)
Se5—Ge2—Se4110.10 (4)Se7xii—K1—K4vii56.64 (3)
Se5—Ge2—Se8iii106.21 (4)Se5xiii—K1—K4vii91.81 (4)
Se4—Ge2—Se8iii108.04 (4)Ge3xii—K1—K4vii88.53 (4)
Se5—Ge2—Se6106.89 (4)K3v—K1—K4vii126.72 (5)
Se4—Ge2—Se6107.47 (4)K2xi—K1—K4vii124.61 (4)
Se8iii—Ge2—Se6118.02 (4)Se6ii—K2—Se3122.37 (5)
Se9—Ge3—Se5ii106.77 (4)Se6ii—K2—Se10xi85.67 (4)
Se9—Ge3—Se7104.41 (4)Se3—K2—Se10xi140.62 (6)
Se5ii—Ge3—Se7109.42 (4)Se6ii—K2—Se9vi117.77 (5)
Se9—Ge3—Se1108.11 (4)Se3—K2—Se9vi105.06 (4)
Se5ii—Ge3—Se1109.06 (4)Se10xi—K2—Se9vi80.26 (4)
Se7—Ge3—Se1118.41 (3)Se6ii—K2—Se166.48 (3)
Se9—Ge3—K1iv63.87 (4)Se3—K2—Se159.48 (3)
Se5ii—Ge3—K1iv70.55 (3)Se10xi—K2—Se1151.02 (5)
Se7—Ge3—K1iv69.59 (3)Se9vi—K2—Se1119.03 (5)
Se1—Ge3—K1iv170.69 (4)Se6ii—K2—Se8ii155.99 (5)
Se1—Ge4—Se6ii111.61 (4)Se3—K2—Se8ii63.83 (3)
Se1—Ge4—Se2105.31 (4)Se10xi—K2—Se8ii79.71 (4)
Se6ii—Ge4—Se2112.11 (4)Se9vi—K2—Se8ii78.53 (3)
Se1—Ge4—Se10103.52 (4)Se1—K2—Se8ii123.18 (4)
Se6ii—Ge4—Se10107.97 (4)Se6ii—K2—Se6v88.25 (4)
Se2—Ge4—Se10116.00 (4)Se3—K2—Se6v85.24 (4)
Se1—Ge4—K3v70.00 (3)Se10xi—K2—Se6v67.14 (3)
Se6ii—Ge4—K3v165.69 (4)Se9vi—K2—Se6v136.72 (5)
Se2—Ge4—K3v80.24 (3)Se1—K2—Se6v102.59 (4)
Se10—Ge4—K3v58.62 (3)Se8ii—K2—Se6v68.58 (3)
Ge4—Se1—Ge3105.83 (4)Se6ii—K2—Se5ii66.18 (3)
Ge4—Se1—K284.27 (3)Se3—K2—Se5ii105.73 (4)
Ge3—Se1—K289.12 (3)Se10xi—K2—Se5ii111.23 (4)
Ge4—Se1—K3v76.36 (3)Se9vi—K2—Se5ii63.77 (3)
Ge3—Se1—K3v133.58 (4)Se1—K2—Se5ii65.82 (3)
K2—Se1—K3v136.35 (4)Se8ii—K2—Se5ii137.13 (5)
Ge4—Se2—Ge1iii111.12 (3)Se6v—K2—Se5ii154.29 (5)
Ge4—Se2—K3iii161.33 (4)Se6ii—K2—K4vi132.29 (6)
Ge1iii—Se2—K3iii79.56 (4)Se3—K2—K4vi54.62 (4)
Ge1—Se3—K391.87 (4)Se10xi—K2—K4vi128.04 (5)
Ge1—Se3—K299.19 (4)Se9vi—K2—K4vi52.69 (4)
K3—Se3—K289.29 (4)Se1—K2—K4vi79.42 (4)
Ge1—Se3—K1v88.32 (4)Se8ii—K2—K4vi71.29 (4)
K3—Se3—K1v86.48 (4)Se6v—K2—K4vi132.68 (5)
K2—Se3—K1v171.51 (4)Se5ii—K2—K4vi69.90 (4)
Ge1—Se3—K4vi98.40 (4)Se6ii—K2—K390.20 (4)
K3—Se3—K4vi160.00 (5)Se3—K2—K344.63 (3)
K2—Se3—K4vi72.21 (4)Se10xi—K2—K3117.56 (5)
K1v—Se3—K4vi110.82 (5)Se9vi—K2—K3148.88 (5)
Ge2—Se4—K498.50 (4)Se1—K2—K357.59 (3)
Ge2—Se4—K1vii99.76 (4)Se8ii—K2—K380.00 (4)
K4—Se4—K1vii103.65 (5)Se6v—K2—K350.46 (3)
Ge2—Se4—K3v98.03 (4)Se5ii—K2—K3123.40 (4)
K4—Se4—K3v118.50 (5)K4vi—K2—K398.95 (5)
K1vii—Se4—K3v130.79 (4)Se6ii—K2—K1xi124.08 (4)
Ge2—Se5—Ge3viii109.10 (3)Se3—K2—K1xi112.76 (4)
Ge2—Se5—K483.63 (4)Se10xi—K2—K1xi42.26 (3)
Ge3viii—Se5—K4166.82 (4)Se9vi—K2—K1xi49.44 (3)
Ge2—Se5—K2viii87.00 (4)Se1—K2—K1xi166.05 (5)
Ge3viii—Se5—K2viii89.49 (3)Se8ii—K2—K1xi51.60 (3)
K4—Se5—K2viii94.72 (4)Se6v—K2—K1xi87.58 (4)
Ge2—Se5—K1ix128.71 (4)Se5ii—K2—K1xi108.43 (4)
Ge3viii—Se5—K1ix74.21 (3)K4vi—K2—K1xi86.66 (4)
K4—Se5—K1ix95.33 (4)K3—K2—K1xi126.65 (5)
K2viii—Se5—K1ix143.75 (4)Se6ii—K2—K3xi46.55 (3)
Ge4viii—Se6—Ge2105.79 (3)Se3—K2—K3xi161.67 (5)
Ge4viii—Se6—K2viii90.04 (4)Se10xi—K2—K3xi40.30 (3)
Ge2—Se6—K2viii91.69 (4)Se9vi—K2—K3xi93.19 (4)
Ge4viii—Se6—K3v166.30 (4)Se1—K2—K3xi112.99 (4)
Ge2—Se6—K3v87.68 (4)Se8ii—K2—K3xi119.72 (4)
K2viii—Se6—K3v92.03 (4)Se6v—K2—K3xi80.20 (4)
Ge4viii—Se6—K2v88.32 (3)Se5ii—K2—K3xi83.63 (4)
Ge2—Se6—K2v165.46 (4)K4vi—K2—K3xi143.28 (5)
K2viii—Se6—K2v91.75 (4)K3—K2—K3xi117.06 (4)
K3v—Se6—K2v78.09 (4)K1xi—K2—K3xi77.86 (3)
Ge1iii—Se7—Ge398.20 (4)Se3—K3—Se10111.20 (6)
Ge1iii—Se7—K1vii80.73 (4)Se3—K3—Se10v82.19 (4)
Ge3—Se7—K1vii134.92 (4)Se10—K3—Se10v98.16 (5)
Ge1iii—Se7—K1iv125.24 (4)Se3—K3—Se4v137.92 (6)
Ge3—Se7—K1iv74.58 (3)Se10—K3—Se4v97.61 (4)
K1vii—Se7—K1iv141.46 (3)Se10v—K3—Se4v124.39 (5)
Ge1viii—Se8—Ge2i104.85 (4)Se3—K3—Se6v87.29 (4)
Ge1viii—Se8—K2viii89.79 (3)Se10—K3—Se6v81.47 (4)
Ge2i—Se8—K2viii160.28 (4)Se10v—K3—Se6v168.57 (6)
Ge1viii—Se8—K1v165.28 (5)Se4v—K3—Se6v66.81 (3)
Ge2i—Se8—K1v88.51 (4)Se3—K3—Se2i71.47 (4)
K2viii—Se8—K1v78.78 (4)Se10—K3—Se2i156.24 (5)
Ge3—Se9—K493.85 (4)Se10v—K3—Se2i105.56 (4)
Ge3—Se9—K4vi102.68 (4)Se4v—K3—Se2i70.12 (4)
K4—Se9—K4vi129.58 (4)Se6v—K3—Se2i75.01 (3)
Ge3—Se9—K2x153.05 (4)Se3—K3—Se1v143.22 (5)
K4—Se9—K2x71.65 (4)Se10—K3—Se1v79.53 (4)
K4vi—Se9—K2x104.03 (4)Se10v—K3—Se1v61.20 (3)
Ge3—Se9—K1iv83.89 (4)Se4v—K3—Se1v69.98 (4)
K4—Se9—K1iv119.43 (5)Se6v—K3—Se1v129.49 (5)
K4vi—Se9—K1iv109.57 (5)Se2i—K3—Se1v113.06 (5)
K2x—Se9—K1iv83.93 (4)Se3—K3—Ge4v112.46 (5)
Ge4—Se10—K1108.99 (5)Se10—K3—Ge4v106.30 (4)
Ge4—Se10—K3104.87 (4)Se10v—K3—Ge4v37.93 (2)
K1—Se10—K3142.83 (5)Se4v—K3—Ge4v86.46 (4)
Ge4—Se10—K2xi96.19 (4)Se6v—K3—Ge4v153.08 (6)
K1—Se10—K2xi92.71 (4)Se2i—K3—Ge4v93.50 (4)
K3—Se10—K2xi98.54 (4)Se1v—K3—Ge4v33.65 (2)
Ge4—Se10—K3v83.45 (4)Se3—K3—K3v99.58 (6)
K1—Se10—K3v87.13 (4)Se10—K3—K3v50.10 (4)
K3—Se10—K3v81.84 (5)Se10v—K3—K3v48.06 (3)
K2xi—Se10—K3v179.54 (5)Se4v—K3—K3v122.49 (6)
Se10—K1—Se3v83.82 (4)Se6v—K3—K3v130.41 (6)
Se10—K1—Se4vii113.87 (5)Se2i—K3—K3v153.60 (7)
Se3v—K1—Se4vii116.80 (5)Se1v—K3—K3v59.34 (4)
Se10—K1—Se9xii80.14 (4)Ge4v—K3—K3v66.40 (4)
Se3v—K1—Se9xii110.40 (5)Se3—K3—K1v47.71 (3)
Se4vii—K1—Se9xii131.67 (5)Se10—K3—K1v131.72 (5)
Se10—K1—Se7vii138.23 (5)Se10v—K3—K1v44.51 (3)
Se3v—K1—Se7vii59.50 (3)Se4v—K3—K1v127.26 (5)
Se4vii—K1—Se7vii71.92 (4)Se6v—K3—K1v128.57 (5)
Se9xii—K1—Se7vii128.77 (5)Se2i—K3—K1v68.47 (4)
Se10—K1—Se8v80.18 (4)Se1v—K3—K1v98.21 (4)
Se3v—K1—Se8v161.84 (6)Ge4v—K3—K1v65.24 (3)
Se4vii—K1—Se8v63.21 (3)K3v—K3—K1v86.98 (5)
Se9xii—K1—Se8v75.27 (4)Se3—K3—K246.08 (3)
Se7vii—K1—Se8v131.15 (5)Se10—K3—K277.01 (4)
Se10—K1—Se7xii130.48 (5)Se10v—K3—K2117.23 (5)
Se3v—K1—Se7xii131.87 (5)Se4v—K3—K2118.23 (5)
Se4vii—K1—Se7xii82.65 (4)Se6v—K3—K251.46 (3)
Se9xii—K1—Se7xii57.56 (3)Se2i—K3—K290.73 (4)
Se7vii—K1—Se7xii90.81 (4)Se1v—K3—K2155.97 (5)
Se8v—K1—Se7xii66.04 (3)Ge4v—K3—K2154.80 (5)
Se10—K1—Se5xiii118.96 (5)K3v—K3—K2100.70 (6)
Se3v—K1—Se5xiii73.76 (4)K1v—K3—K293.54 (4)
Se4vii—K1—Se5xiii127.01 (5)Se3—K3—K2xi109.01 (5)
Se9xii—K1—Se5xiii57.82 (3)Se10—K3—K2xi41.16 (3)
Se7vii—K1—Se5xiii71.91 (3)Se10v—K3—K2xi139.32 (5)
Se8v—K1—Se5xiii121.81 (5)Se4v—K3—K2xi73.39 (4)
Se7xii—K1—Se5xiii60.61 (3)Se6v—K3—K2xi41.42 (3)
Se10—K1—Ge3xii111.83 (5)Se2i—K3—K2xi115.10 (4)
Se3v—K1—Ge3xii107.08 (5)Se1v—K3—K2xi101.72 (4)
Se4vii—K1—Ge3xii118.34 (4)Ge4v—K3—K2xi135.32 (4)
Se9xii—K1—Ge3xii32.24 (2)K3v—K3—K2xi91.26 (5)
Se7vii—K1—Ge3xii98.47 (4)K1v—K3—K2xi155.67 (5)
Se8v—K1—Ge3xii86.93 (4)K2—K3—K2xi62.94 (4)
Se7xii—K1—Ge3xii35.83 (2)Se4—K4—Se9112.11 (5)
Se5xiii—K1—Ge3xii35.24 (2)Se4—K4—Se9x108.09 (6)
Se10—K1—K3v48.36 (3)Se9—K4—Se9x108.77 (5)
Se3v—K1—K3v45.81 (3)Se4—K4—Se3x128.74 (6)
Se4vii—K1—K3v101.35 (5)Se9—K4—Se3x106.52 (5)
Se9xii—K1—K3v119.14 (5)Se9x—K4—Se3x89.23 (4)
Se7vii—K1—K3v89.99 (4)Se4—K4—Se567.66 (4)
Se8v—K1—K3v116.11 (5)Se9—K4—Se5173.44 (7)
Se7xii—K1—K3v175.97 (5)Se9x—K4—Se565.76 (4)
Se5xiii—K1—K3v115.98 (5)Se3x—K4—Se577.56 (4)
Ge3xii—K1—K3v140.14 (5)Se4—K4—K2x159.96 (7)
Se10—K1—K2xi45.02 (3)Se9—K4—K2x55.66 (4)
Se3v—K1—K2xi121.25 (5)Se9x—K4—K2x91.57 (4)
Se4vii—K1—K2xi110.45 (5)Se3x—K4—K2x53.18 (4)
Se9xii—K1—K2xi46.64 (3)Se5—K4—K2x126.51 (5)
Se7vii—K1—K2xi175.36 (5)Se4—K4—K1vii41.05 (3)
Se8v—K1—K2xi49.62 (3)Se9—K4—K1vii101.91 (4)
Se7xii—K1—K2xi85.61 (4)Se9x—K4—K1vii144.16 (5)
Se5xiii—K1—K2xi103.70 (4)Se3x—K4—K1vii99.56 (5)
Ge3xii—K1—K2xi76.90 (4)Se5—K4—K1vii82.21 (4)
K3v—K1—K2xi93.39 (4)K2x—K4—K1vii121.49 (5)
Symmetry codes: (i) x1, y, z; (ii) x, y+1, z; (iii) x+1, y, z; (iv) x, y+3/2, z1/2; (v) x+1, y+1, z+1; (vi) x+1, y+1/2, z+1/2; (vii) x+2, y+1, z+1; (viii) x, y1, z; (ix) x, y+1/2, z1/2; (x) x+1, y1/2, z+1/2; (xi) x+1, y+2, z+1; (xii) x, y+3/2, z+1/2; (xiii) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaK4Ge4Se10
Mr1236.36
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)9.9796 (8), 9.7047 (8), 23.184 (2)
β (°) 94.508 (2)
V3)2238.4 (3)
Z4
Radiation typeMo Kα
µ (mm1)22.31
Crystal size (mm)0.26 × 0.12 × 0.06
Data collection
DiffractometerBruker SMART CCD area detector
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.054, 0.262
No. of measured, independent and
observed [I > 2σ(I)] reflections
19344, 4823, 3896
Rint0.069
(sin θ/λ)max1)0.639
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.103, 1.04
No. of reflections4823
No. of parameters164
Δρmax, Δρmin (e Å3)1.72, 1.47

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2005), SHELXL97.

Selected bond lengths (Å) top
Ge1—Se7i2.2492 (10)Ge3—Se92.1288 (9)
Ge1—Se32.3105 (10)Ge3—Se5ii2.3795 (10)
Ge1—Se8ii2.3583 (10)Ge3—Se72.4092 (10)
Ge1—Se2i2.4943 (11)Ge3—Se12.5131 (10)
Ge2—Se52.2366 (9)Ge4—Se12.2335 (9)
Ge2—Se42.2613 (9)Ge4—Se6ii2.3735 (9)
Ge2—Se8iii2.3769 (10)Ge4—Se22.3755 (10)
Ge2—Se62.5384 (10)Ge4—Se102.4238 (10)
Symmetry codes: (i) x1, y, z; (ii) x, y+1, z; (iii) x+1, y, z.
 

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