Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807027705/wm2119sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807027705/wm2119Isup2.hkl |
Key indicators
- Single-crystal X-ray study
- T = 298 K
- Mean (e-O) = 0.007 Å
- Disorder in main residue
- R factor = 0.045
- wR factor = 0.051
- Data-to-parameter ratio = 15.1
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ? PLAT077_ALERT_4_C Unitcell contains non-integer number of atoms .. ? PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for O7 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for O8 PLAT301_ALERT_3_C Main Residue Disorder ......................... 5.00 Perc. PLAT711_ALERT_1_C BOND Unknown or Inconsistent Label .......... X1 X1 O7 PLAT711_ALERT_1_C BOND Unknown or Inconsistent Label .......... X1 X1 O8 PLAT711_ALERT_1_C BOND Unknown or Inconsistent Label .......... X1 X1 O9 PLAT711_ALERT_1_C BOND Unknown or Inconsistent Label .......... X1 X1 O10 PLAT712_ALERT_1_C ANGLE Unknown or Inconsistent Label .......... X1 O7 X1 O8 PLAT712_ALERT_1_C ANGLE Unknown or Inconsistent Label .......... X1 O7 X1 O9 PLAT712_ALERT_1_C ANGLE Unknown or Inconsistent Label .......... X1 O8 X1 O9 PLAT712_ALERT_1_C ANGLE Unknown or Inconsistent Label .......... X1 O7 X1 O10 PLAT712_ALERT_1_C ANGLE Unknown or Inconsistent Label .......... X1 O8 X1 O10 PLAT712_ALERT_1_C ANGLE Unknown or Inconsistent Label .......... X1 O9 X1 O10 PLAT755_ALERT_4_C D-H Calc 0.86000, Rep 0.857(6) ...... Senseless su O1 -H1 1.555 1.555 PLAT755_ALERT_4_C D-H Calc 0.82000, Rep 0.817(6) ...... Senseless su O2 -H2 1.555 1.555 PLAT755_ALERT_4_C D-H Calc 0.82000, Rep 0.817(6) ...... Senseless su O3 -H3 1.555 1.555 PLAT755_ALERT_4_C D-H Calc 0.85000, Rep 0.848(6) ...... Senseless su O4 -H4 1.555 1.555 PLAT755_ALERT_4_C D-H Calc 0.86000, Rep 0.856(6) ...... Senseless su O5 -H5 1.555 1.555 PLAT755_ALERT_4_C D-H Calc 0.83000, Rep 0.826(6) ...... Senseless su O6 -H6 1.555 1.555 PLAT756_ALERT_4_C H...A Calc 1.92000, Rep 1.924(7) ...... Senseless su H1 -O9 1.555 1.545 PLAT756_ALERT_4_C H...A Calc 1.97000, Rep 1.967(7) ...... Senseless su H2 -O9 1.555 1.555 PLAT756_ALERT_4_C H...A Calc 1.97000, Rep 1.972(7) ...... Senseless su H3 -O10 1.555 1.655 PLAT756_ALERT_4_C H...A Calc 1.81000, Rep 1.815(7) ...... Senseless su H4 -O8 1.555 1.645 PLAT756_ALERT_4_C H...A Calc 1.87000, Rep 1.868(6) ...... Senseless su H5 -O7 1.555 1.655 PLAT756_ALERT_4_C H...A Calc 1.95000, Rep 1.946(6) ...... Senseless su H6 -O7 1.555 1.545 PLAT758_ALERT_4_C D-H..A Calc 169.00, Rep 168.7(5) ...... Senseless su O2 -H2 -O9 1.555 1.555 1.555 PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd. # 3 O4 S0.63 Se0.37 PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd. # 5 K
Alert level G PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 7
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 30 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 11 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 2 ALERT type 2 Indicator that the structure model may be wrong or deficient 2 ALERT type 3 Indicator that the structure quality may be low 16 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
For the structures of the end-members of this solid solution series, see K2SO4·Te(OH)6 (Zilber et al., 1980) and K2SeO4·Te(OH)6 (Dammak et al., 2005).
Transparent, colorless single crystals of compound (I) were grown at room temperature by slow evaporation of an aqueous solution consisting of a mixture of Te(OH)6 (Aldrich, 99%), K2SeO4 (Aldrich, 99.99%) and K2SO4 (Aldrich, 99%) in the stoichiometric ratio 1:0.5:0.5.
Hydrogen atoms on Te(OH)6 groups were located in a difference map and were refined with restrained distances between 0.81 (1) and 0.86 (1) Å and a common Uiso parameter. For the refinement of the occupation factors for S and Se, their sum was constrained to be equal to 1. The highest peak and the deepest hole in the final Fourier map are located 0.04 and 0.57 Å, respectively, from the X site (X = S, Se).
Fig. 1 shows a projection of the title structure (I) on the ab plane. The structure consists of planes of Te(OH)6 octahedra alternating with planes of statistically occupied XO4 tetrahedra (X = S, Se). The Te(OH)6 layers extend parallel to the ac plane at y = 0, whereas the parallel XO4 layers are at y ≈ 0.5. The K+ cations are situated between the layers.
The two independent Te atoms in (I) occupy inversion centres (Fig. 2), with very similar Te—O distances between 1.900 (6) and 1.921 (6) Å and O—Te—O angles between 88.8 (3) and 91.20 (3)°. In the isostructural end-member K2SO4·Te(OH)6 (KSTe) (Zilber et al., 1980), the Te—O distances are nearly the same and vary from 1.914 (5) to 1.938 (5) Å, whilst in K2SeO4·Te(OH)6 (KSeTe) they are between 1.913 (2) and 1.919 (2) Å (Dammak et al., 2005).
The X—O distances of the slightly distorted XO4 tetrahedra vary from 1.460 (7) to 1.508 (6) Å, with O—X—O angles between 108.3 (4) and 111.0 (4)°. In the KSTe structure, the S—O distances range from 1.453 (5) to 1.503 (5) Å and in the KSeTe homologue, the Se—O distances vary from 1.627 (7) to 1.659 (7) Å.
The two K+ cations are both in eightfold coordination with distances ranging between 2.709 (6) and 3.267 (8) Å. K1+ is coordinated by three O atoms belonging to two XO4 tetrahedra, by one O atom of a Te1O6 octahedron, and by four O atoms of three Te2O6 octahedra. The environment of K2+ consists of three O atoms belonging to three XO4 tetrahedra, of one O atom from a Te2O6 octahedron, and of four O atoms from three Te1O6 octahedra.
Interplanar O—H···O hydrogen bonding between the Te(OH)6 octahedra and the XO4 tetrahedra helps to consolidate the structural set-up. In consequence, all H atoms of the hydroxyl groups participate in the formation of hydrogen bonding. In the XO4 group, two oxygen atoms are acceptors of one H atom, whereas the other O atoms are acceptors of two H atoms. The O···O distances vary from 2.654 (9) to 2.780 (9) Å and the O—H···O angles range from 164.3 (4) and 175.6 (5)° (Table 1, Fig. 3).
For the structures of the end-members of this solid solution series, see K2SO4·Te(OH)6 (Zilber et al., 1980) and K2SeO4·Te(OH)6 (Dammak et al., 2005).
Data collection: COLLECT (Nonius, 2001); cell refinement: DENZO/SCALEPACK; data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: DIAMOND (Brandenburg & Berndt, 1999); software used to prepare material for publication: CRYSTALS.
K2(SO4)0.63(SeO4)0.37Te(OH)6 | Z = 2 |
Mr = 421.16 | F(000) = 397.250 |
Triclinic, P1 | Dx = 2.961 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.2463 (2) Å | Cell parameters from 7138 reflections |
b = 6.6470 (2) Å | θ = 2.7–30.1° |
c = 13.1326 (4) Å | µ = 5.63 mm−1 |
α = 102.138 (2)° | T = 298 K |
β = 90.073 (2)° | Prism, colourless |
γ = 116.943 (1)° | 0.15 × 0.14 × 0.10 mm |
V = 472.28 (3) Å3 |
Nonius KappaCCD diffractometer | 1719 reflections with I > 3σ(I) |
Graphite monochromator | Rint = 0.038 |
φ rotation scans with 2° width | θmax = 30.2°, θmin = 1.6° |
Absorption correction: multi-scan (MULABS in PLATON; Spek, 2003) | h = −8→8 |
Tmin = 0.447, Tmax = 0.569 | k = −9→9 |
69116 measured reflections | l = −18→18 |
2787 independent reflections |
Refinement on F | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.045 | All H-atom parameters refined |
wR(F2) = 0.051 | Method, part 1, Chebychev polynomial, [Watkin (1994). Acta Cryst.
A50, 411–437; Prince,
(1982). Mathematical Techniques in Crystallography and Materials
Science. Springer-Verlag: New York.]
[weight] = 1.0/[A0*T0(x) + A1*T1(x) ··· + An-1]*Tn-1(x)]
where Ai are the Chebychev coefficients listed below and x = F /Fmax Method = Robust Weighting (Prince, 1982) W = [weight] * [1-(deltaF/6*sigmaF)2]2 Ai are: 4.11 -3.38 2.64 |
S = 1.09 | (Δ/σ)max = 0.002 |
1719 reflections | Δρmax = 2.40 e Å−3 |
114 parameters | Δρmin = −2.99 e Å−3 |
7 restraints |
K2(SO4)0.63(SeO4)0.37Te(OH)6 | γ = 116.943 (1)° |
Mr = 421.16 | V = 472.28 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.2463 (2) Å | Mo Kα radiation |
b = 6.6470 (2) Å | µ = 5.63 mm−1 |
c = 13.1326 (4) Å | T = 298 K |
α = 102.138 (2)° | 0.15 × 0.14 × 0.10 mm |
β = 90.073 (2)° |
Nonius KappaCCD diffractometer | 2787 independent reflections |
Absorption correction: multi-scan (MULABS in PLATON; Spek, 2003) | 1719 reflections with I > 3σ(I) |
Tmin = 0.447, Tmax = 0.569 | Rint = 0.038 |
69116 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 7 restraints |
wR(F2) = 0.051 | All H-atom parameters refined |
S = 1.09 | Δρmax = 2.40 e Å−3 |
1719 reflections | Δρmin = −2.99 e Å−3 |
114 parameters |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Te1 | 0.0000 | 0.0000 | 0.0000 | 0.0150 | |
Te2 | 0.5000 | 0.0000 | 0.5000 | 0.0144 | |
Se1 | −0.24991 (17) | 0.46625 (17) | 0.24814 (17) | 0.0439 | 0.368 (7) |
S1 | −0.24991 (17) | 0.46625 (17) | 0.24814 (17) | 0.0439 | 0.632 (7) |
K1 | 0.1921 (4) | 0.2576 (3) | 0.35079 (18) | 0.0274 | |
K2 | 0.4207 (4) | −0.2342 (3) | 0.14873 (17) | 0.0254 | |
O1 | −0.0604 (11) | −0.0373 (10) | 0.1399 (5) | 0.0232 | |
O2 | −0.1770 (12) | 0.1704 (11) | 0.0061 (5) | 0.0251 | |
O3 | 0.2905 (11) | 0.2817 (10) | 0.0548 (6) | 0.0269 | |
O4 | 0.7680 (10) | −0.0037 (10) | 0.4321 (5) | 0.0250 | |
O5 | 0.6055 (11) | 0.3137 (9) | 0.4891 (5) | 0.0215 | |
O6 | 0.3083 (10) | −0.1107 (10) | 0.3668 (5) | 0.0233 | |
O7 | −0.1044 (11) | 0.4714 (11) | 0.3412 (5) | 0.0260 | |
O8 | −0.3641 (13) | 0.6150 (12) | 0.2807 (6) | 0.0281 | |
O9 | −0.0842 (12) | 0.5509 (12) | 0.1687 (6) | 0.0312 | |
O10 | −0.4411 (12) | 0.2270 (10) | 0.2057 (6) | 0.0301 | |
H1 | −0.0693 | −0.1671 | 0.1452 | 0.0436* | |
H2 | −0.1419 | 0.2746 | 0.0589 | 0.0436* | |
H3 | 0.3657 | 0.2491 | 0.0937 | 0.0436* | |
H4 | 0.7229 | −0.1343 | 0.3896 | 0.0436* | |
H5 | 0.6985 | 0.3395 | 0.4404 | 0.0436* | |
H6 | 0.1875 | −0.2315 | 0.3702 | 0.0436* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Te1 | 0.01489 (9) | 0.01533 (9) | 0.01406 (9) | 0.00653 (9) | 0.00131 (9) | 0.00335 (9) |
Te2 | 0.01472 (9) | 0.01349 (9) | 0.01512 (9) | 0.00649 (9) | 0.00155 (9) | 0.00350 (9) |
Se1 | 0.03752 (17) | 0.04897 (17) | 0.03836 (17) | 0.01470 (17) | 0.00249 (17) | 0.00931 (17) |
S1 | 0.03752 (17) | 0.04897 (17) | 0.03836 (17) | 0.01470 (17) | 0.00249 (17) | 0.00931 (17) |
K1 | 0.0242 (8) | 0.0260 (8) | 0.0370 (11) | 0.0156 (7) | 0.0043 (7) | 0.0079 (7) |
K2 | 0.0244 (8) | 0.0227 (8) | 0.0346 (10) | 0.0146 (7) | 0.0013 (7) | 0.0093 (7) |
O1 | 0.033 (3) | 0.025 (3) | 0.016 (3) | 0.015 (2) | 0.007 (2) | 0.009 (2) |
O2 | 0.031 (3) | 0.028 (3) | 0.024 (3) | 0.022 (3) | 0.000 (2) | 0.003 (2) |
O3 | 0.025 (3) | 0.016 (2) | 0.035 (4) | 0.004 (2) | −0.007 (2) | 0.008 (2) |
O4 | 0.019 (3) | 0.020 (3) | 0.032 (3) | 0.008 (2) | 0.008 (2) | 0.001 (2) |
O5 | 0.026 (3) | 0.013 (2) | 0.026 (3) | 0.009 (2) | 0.006 (2) | 0.006 (2) |
O6 | 0.024 (3) | 0.019 (3) | 0.020 (3) | 0.004 (2) | −0.004 (2) | 0.006 (2) |
O7 | 0.023 (3) | 0.031 (3) | 0.028 (3) | 0.011 (2) | 0.000 (2) | 0.017 (3) |
O8 | 0.036 (4) | 0.032 (3) | 0.029 (4) | 0.029 (3) | 0.006 (3) | 0.001 (3) |
O9 | 0.032 (3) | 0.030 (3) | 0.033 (4) | 0.013 (3) | 0.006 (3) | 0.012 (3) |
O10 | 0.031 (3) | 0.016 (3) | 0.038 (4) | 0.007 (2) | −0.005 (3) | 0.005 (2) |
Te1—O1i | 1.920 (6) | O4—H4 | 0.848 |
Te1—O3i | 1.915 (6) | O5—H5 | 0.856 |
Te1—O2i | 1.900 (6) | O6—H6 | 0.826 |
Te1—O1 | 1.920 (6) | K1—O4iii | 2.792 (6) |
Te1—O2 | 1.900 (6) | K1—O7 | 2.815 (6) |
Te1—O3 | 1.915 (6) | K1—O5iv | 2.889 (6) |
Te2—O6ii | 1.921 (6) | K1—O6 | 2.897 (6) |
Te2—O5ii | 1.919 (5) | K1—O1 | 2.984 (7) |
Te2—O4ii | 1.905 (6) | K1—O5 | 2.990 (6) |
Te2—O4 | 1.905 (6) | K1—O8v | 3.022 (8) |
Te2—O5 | 1.919 (5) | K1—O10v | 3.032 (8) |
Te2—O6 | 1.921 (6) | K2—O10v | 2.709 (6) |
X1—O7 | 1.508 (6) | K2—O2i | 2.751 (6) |
X1—O8 | 1.460 (7) | K2—O8vi | 2.786 (8) |
X1—O9 | 1.482 (7) | K2—O9vii | 2.852 (7) |
X1—O10 | 1.473 (6) | K2—O1v | 2.908 (7) |
O1—H1 | 0.857 | K2—O3vii | 2.915 (6) |
O2—H2 | 0.817 | K2—O6 | 2.984 (7) |
O3—H3 | 0.817 | K2—O3viii | 3.267 (8) |
O1i—Te1—O3i | 89.9 (3) | O6ii—Te2—O5 | 90.4 (3) |
O1i—Te1—O2i | 91.2 (3) | O5ii—Te2—O5 | 179.994 |
O3i—Te1—O2i | 90.4 (3) | O4ii—Te2—O5 | 90.0 (3) |
O1i—Te1—O1 | 179.994 | O4—Te2—O5 | 90.0 (3) |
O3i—Te1—O1 | 90.1 (3) | O6ii—Te2—O6 | 179.994 |
O2i—Te1—O1 | 88.8 (3) | O5ii—Te2—O6 | 90.4 (3) |
O1i—Te1—O2 | 88.8 (3) | O4ii—Te2—O6 | 89.6 (3) |
O3i—Te1—O2 | 89.6 (3) | O4—Te2—O6 | 90.4 (3) |
O2i—Te1—O2 | 179.994 | O5—Te2—O6 | 89.6 (3) |
O1—Te1—O2 | 91.2 (3) | O7—X1—O8 | 109.8 (4) |
O1i—Te1—O3 | 90.1 (3) | O7—X1—O9 | 108.3 (4) |
O3i—Te1—O3 | 179.994 | O8—X1—O9 | 110.1 (4) |
O2i—Te1—O3 | 89.6 (3) | O7—X1—O10 | 109.3 (4) |
O1—Te1—O3 | 89.9 (3) | O8—X1—O10 | 108.4 (4) |
O2—Te1—O3 | 90.4 (3) | O9—X1—O10 | 111.0 (4) |
O6ii—Te2—O5ii | 89.6 (3) | Te1—O1—H1 | 109.426 |
O6ii—Te2—O4ii | 90.4 (3) | Te1—O2—H2 | 114.986 |
O5ii—Te2—O4ii | 90.0 (3) | Te1—O3—H3 | 105.734 |
O6ii—Te2—O4 | 89.6 (3) | Te2—O4—H4 | 109.438 |
O5ii—Te2—O4 | 90.0 (3) | Te2—O5—H5 | 108.396 |
O4ii—Te2—O4 | 179.994 | Te2—O6—H6 | 106.016 |
Symmetry codes: (i) −x, −y, −z; (ii) −x+1, −y, −z+1; (iii) x−1, y, z; (iv) −x+1, −y+1, −z+1; (v) x+1, y, z; (vi) x+1, y−1, z; (vii) x, y−1, z; (viii) −x+1, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O9vii | 0.86 (1) | 1.92 (1) | 2.780 (9) | 176 (1) |
O2—H2···O9 | 0.82 (1) | 1.97 (1) | 2.773 (10) | 169 (1) |
O3—H3···O10v | 0.82 (1) | 1.97 (1) | 2.778 (9) | 169 (1) |
O4—H4···O8vi | 0.85 (1) | 1.82 (1) | 2.654 (9) | 170 (1) |
O5—H5···O7v | 0.86 (1) | 1.87 (1) | 2.701 (9) | 164 (1) |
O6—H6···O7vii | 0.83 (1) | 1.95 (1) | 2.755 (8) | 166 (1) |
Symmetry codes: (v) x+1, y, z; (vi) x+1, y−1, z; (vii) x, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | K2(SO4)0.63(SeO4)0.37Te(OH)6 |
Mr | 421.16 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 298 |
a, b, c (Å) | 6.2463 (2), 6.6470 (2), 13.1326 (4) |
α, β, γ (°) | 102.138 (2), 90.073 (2), 116.943 (1) |
V (Å3) | 472.28 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 5.63 |
Crystal size (mm) | 0.15 × 0.14 × 0.10 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | Multi-scan (MULABS in PLATON; Spek, 2003) |
Tmin, Tmax | 0.447, 0.569 |
No. of measured, independent and observed [I > 3σ(I)] reflections | 69116, 2787, 1719 |
Rint | 0.038 |
(sin θ/λ)max (Å−1) | 0.707 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.051, 1.09 |
No. of reflections | 1719 |
No. of parameters | 114 |
No. of restraints | 7 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 2.40, −2.99 |
Computer programs: COLLECT (Nonius, 2001), DENZO/SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 1997), CRYSTALS (Betteridge et al., 2003), DIAMOND (Brandenburg & Berndt, 1999), CRYSTALS.
Te1—O1i | 1.920 (6) | K1—O4iii | 2.792 (6) |
Te1—O3i | 1.915 (6) | K1—O7 | 2.815 (6) |
Te1—O2i | 1.900 (6) | K1—O5iv | 2.889 (6) |
Te1—O1 | 1.920 (6) | K1—O6 | 2.897 (6) |
Te1—O2 | 1.900 (6) | K1—O1 | 2.984 (7) |
Te1—O3 | 1.915 (6) | K1—O5 | 2.990 (6) |
Te2—O6ii | 1.921 (6) | K1—O8v | 3.022 (8) |
Te2—O5ii | 1.919 (5) | K1—O10v | 3.032 (8) |
Te2—O4ii | 1.905 (6) | K2—O10v | 2.709 (6) |
Te2—O4 | 1.905 (6) | K2—O2i | 2.751 (6) |
Te2—O5 | 1.919 (5) | K2—O8vi | 2.786 (8) |
Te2—O6 | 1.921 (6) | K2—O9vii | 2.852 (7) |
X1—O7 | 1.508 (6) | K2—O1v | 2.908 (7) |
X1—O8 | 1.460 (7) | K2—O3vii | 2.915 (6) |
X1—O9 | 1.482 (7) | K2—O6 | 2.984 (7) |
X1—O10 | 1.473 (6) | K2—O3viii | 3.267 (8) |
Symmetry codes: (i) −x, −y, −z; (ii) −x+1, −y, −z+1; (iii) x−1, y, z; (iv) −x+1, −y+1, −z+1; (v) x+1, y, z; (vi) x+1, y−1, z; (vii) x, y−1, z; (viii) −x+1, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O9vii | 0.857 (6) | 1.924 (7) | 2.780 (9) | 175.6 (5) |
O2—H2···O9 | 0.817 (6) | 1.967 (7) | 2.773 (10) | 168.7 (5) |
O3—H3···O10v | 0.817 (6) | 1.972 (7) | 2.778 (9) | 169.1 (5) |
O4—H4···O8vi | 0.848 (6) | 1.815 (7) | 2.654 (9) | 169.7 (5) |
O5—H5···O7v | 0.856 (6) | 1.868 (6) | 2.701 (9) | 164.3 (4) |
O6—H6···O7vii | 0.826 (6) | 1.946 (6) | 2.755 (8) | 166.0 (5) |
Symmetry codes: (v) x+1, y, z; (vi) x+1, y−1, z; (vii) x, y−1, z. |
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Fig. 1 shows a projection of the title structure (I) on the ab plane. The structure consists of planes of Te(OH)6 octahedra alternating with planes of statistically occupied XO4 tetrahedra (X = S, Se). The Te(OH)6 layers extend parallel to the ac plane at y = 0, whereas the parallel XO4 layers are at y ≈ 0.5. The K+ cations are situated between the layers.
The two independent Te atoms in (I) occupy inversion centres (Fig. 2), with very similar Te—O distances between 1.900 (6) and 1.921 (6) Å and O—Te—O angles between 88.8 (3) and 91.20 (3)°. In the isostructural end-member K2SO4·Te(OH)6 (KSTe) (Zilber et al., 1980), the Te—O distances are nearly the same and vary from 1.914 (5) to 1.938 (5) Å, whilst in K2SeO4·Te(OH)6 (KSeTe) they are between 1.913 (2) and 1.919 (2) Å (Dammak et al., 2005).
The X—O distances of the slightly distorted XO4 tetrahedra vary from 1.460 (7) to 1.508 (6) Å, with O—X—O angles between 108.3 (4) and 111.0 (4)°. In the KSTe structure, the S—O distances range from 1.453 (5) to 1.503 (5) Å and in the KSeTe homologue, the Se—O distances vary from 1.627 (7) to 1.659 (7) Å.
The two K+ cations are both in eightfold coordination with distances ranging between 2.709 (6) and 3.267 (8) Å. K1+ is coordinated by three O atoms belonging to two XO4 tetrahedra, by one O atom of a Te1O6 octahedron, and by four O atoms of three Te2O6 octahedra. The environment of K2+ consists of three O atoms belonging to three XO4 tetrahedra, of one O atom from a Te2O6 octahedron, and of four O atoms from three Te1O6 octahedra.
Interplanar O—H···O hydrogen bonding between the Te(OH)6 octahedra and the XO4 tetrahedra helps to consolidate the structural set-up. In consequence, all H atoms of the hydroxyl groups participate in the formation of hydrogen bonding. In the XO4 group, two oxygen atoms are acceptors of one H atom, whereas the other O atoms are acceptors of two H atoms. The O···O distances vary from 2.654 (9) to 2.780 (9) Å and the O—H···O angles range from 164.3 (4) and 175.6 (5)° (Table 1, Fig. 3).