Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102007886/br1369sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102007886/br1369Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102007886/br1369IIsup3.hkl |
Single crystals of KMo5O13 were prepared from a mixture of K2CO3, (NH4)6Mo7O24·4H2O and H3BO3 in a molar ratio of 5:1:5. The mixture was ground and then heated in a platinium crucible at 1073 K for 40 h. The mixture was then cooled to room temperature at a rate of 0.1 K min-1. Colourless plates were extracted from the boron glass using hot water. Qualitative analysis of the sample by electron microscope probe revealed that it contained K and Mo.
Transparent and colourless single crystals of KNb1.76Sb3.24O13 were prepared from a mixture of K2CO3, Sb2O3 and Nb2O5 in a molar ratio of 5:2:2. The powder was ground and homogenized with boric acid (H3BO3) as a flux, then heated in a porcelain crucible in air to 1273 K. This temperature was held for 20 h, then the mixture was cooled to 773 K at a rate of 6 K h-1 and maintained at that temperature for 2 h, before being cooled to room temperature at a rate of 30 K h-1. Single crystals were extracted from the boron glass using hot water. Qualitative analysis of the single crystals by electron microscope probe revealed that they contained K, Nb and Sb.
For both compounds, data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992). Cell refinement: CAD-4 EXPRESS for (I); CAD-4 EXPRESS and WinGX (Farrugia, 1999) for (II). For both compounds, data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97.
KMo5O13 | F(000) = 1331 |
Mr = 726.79 | Dx = 4.847 Mg m−3 |
Orthorhombic, Cmcm | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2c 2 | Cell parameters from 24 reflections |
a = 6.6027 (10) Å | θ = 9.1–14.0° |
b = 8.9552 (10) Å | µ = 6.62 mm−1 |
c = 16.844 (2) Å | T = 293 K |
V = 996.0 (2) Å3 | Plate, colourless |
Z = 4 | 0.09 × 0.07 × 0.02 mm |
Enraf-Nonius CAD-4 diffractometer | 740 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.008 |
Graphite monochromator | θmax = 30.0°, θmin = 2.4° |
ω/2θ scans | h = −1→9 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→12 |
Tmin = 0.601, Tmax = 0.910 | l = 0→23 |
2790 measured reflections | 2 standard reflections every 120 min |
812 independent reflections | intensity decay: 0.6% |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.037 | w = 1/[σ2(Fo2) + (0.0499P)2 + 28.8946P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.100 | (Δ/σ)max < 0.001 |
S = 1.22 | Δρmax = 1.94 e Å−3 |
812 reflections | Δρmin = −2.48 e Å−3 |
58 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0062 (4) |
KMo5O13 | V = 996.0 (2) Å3 |
Mr = 726.79 | Z = 4 |
Orthorhombic, Cmcm | Mo Kα radiation |
a = 6.6027 (10) Å | µ = 6.62 mm−1 |
b = 8.9552 (10) Å | T = 293 K |
c = 16.844 (2) Å | 0.09 × 0.07 × 0.02 mm |
Enraf-Nonius CAD-4 diffractometer | 740 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.008 |
Tmin = 0.601, Tmax = 0.910 | 2 standard reflections every 120 min |
2790 measured reflections | intensity decay: 0.6% |
812 independent reflections |
R[F2 > 2σ(F2)] = 0.037 | 0 restraints |
wR(F2) = 0.100 | w = 1/[σ2(Fo2) + (0.0499P)2 + 28.8946P] where P = (Fo2 + 2Fc2)/3 |
S = 1.22 | Δρmax = 1.94 e Å−3 |
812 reflections | Δρmin = −2.48 e Å−3 |
58 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Mo1 | 0.0000 | 0.0000 | 0.5000 | 0.0048 (2) | |
Mo2 | 0.0000 | 0.23165 (7) | 0.36166 (4) | 0.0048 (2) | |
Mo3 | 0.0000 | 0.38575 (7) | 0.57726 (4) | 0.0049 (2) | |
K | 0.0000 | 0.1278 (4) | 0.7500 | 0.0309 (8) | |
O1 | 0.0000 | 0.1878 (13) | 0.2500 | 0.023 (2) | |
O2 | 0.2035 (9) | 0.2732 (6) | 0.6322 (3) | 0.0223 (11) | |
O3 | −0.3110 (12) | 0.0000 | 0.5000 | 0.0195 (14) | |
O4 | 0.0000 | 0.2256 (8) | 0.4907 (5) | 0.0202 (15) | |
O5 | 0.0000 | 0.5535 (8) | 0.6499 (5) | 0.0213 (15) | |
O6 | 0.0000 | 0.0147 (8) | 0.3869 (4) | 0.0205 (15) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Mo1 | 0.0062 (4) | 0.0046 (4) | 0.0035 (4) | 0.000 | 0.000 | 0.0007 (3) |
Mo2 | 0.0064 (3) | 0.0041 (3) | 0.0038 (3) | 0.000 | 0.000 | 0.0002 (2) |
Mo3 | 0.0064 (4) | 0.0042 (3) | 0.0042 (3) | 0.000 | 0.000 | 0.0003 (2) |
K | 0.047 (2) | 0.0259 (17) | 0.0192 (16) | 0.000 | 0.000 | 0.000 |
O1 | 0.030 (6) | 0.028 (6) | 0.012 (4) | 0.000 | 0.000 | 0.000 |
O2 | 0.025 (3) | 0.022 (2) | 0.020 (2) | 0.001 (2) | −0.004 (2) | 0.0027 (19) |
O3 | 0.023 (3) | 0.020 (3) | 0.015 (3) | 0.000 | 0.000 | 0.003 (3) |
O4 | 0.026 (4) | 0.017 (3) | 0.018 (4) | 0.000 | 0.000 | 0.001 (3) |
O5 | 0.030 (4) | 0.014 (3) | 0.020 (3) | 0.000 | 0.000 | 0.001 (3) |
O6 | 0.032 (4) | 0.016 (3) | 0.013 (3) | 0.000 | 0.000 | 0.002 (3) |
Mo1—O6i | 1.909 (7) | Mo2—O4 | 2.174 (8) |
Mo1—O4i | 2.026 (7) | Mo3—O2 | 1.917 (5) |
Mo1—O3i | 2.054 (8) | Mo3—O5 | 1.937 (8) |
Mo1—Mo2i | 3.1198 (7) | Mo3—O4 | 2.046 (8) |
Mo2—O1 | 1.921 (3) | Mo3—O3iv | 2.073 (5) |
Mo2—O5ii | 1.934 (7) | K—O6v | 2.636 (7) |
Mo2—O2iii | 1.961 (6) | K—O2vi | 2.727 (6) |
Mo2—O6 | 1.989 (7) | K—O1i | 2.826 (12) |
O2—Mo3—O2vii | 89.0 (3) | O4i—Mo1—O4 | 180.0 (4) |
O2—Mo3—O5 | 95.9 (2) | O6i—Mo1—O3i | 90.000 (1) |
O2vii—Mo3—O5 | 95.9 (2) | O6—Mo1—O3i | 90.000 (1) |
O2—Mo3—O4 | 88.6 (2) | O4i—Mo1—O3i | 90.000 (1) |
O2vii—Mo3—O4 | 88.6 (2) | O4—Mo1—O3i | 90.000 (2) |
O5—Mo3—O4 | 173.7 (3) | O6i—Mo1—O3 | 90.000 (1) |
O2—Mo3—O3iv | 98.1 (3) | O6—Mo1—O3 | 90.000 (1) |
O2vii—Mo3—O3iv | 169.8 (2) | O4i—Mo1—O3 | 90.000 (2) |
O5—Mo3—O3iv | 90.79 (18) | O4—Mo1—O3 | 90.000 (1) |
O4—Mo3—O3iv | 84.17 (17) | O3i—Mo1—O3 | 180.000 (1) |
O2—Mo3—O3viii | 169.8 (2) | O1—Mo2—O5ii | 96.0 (4) |
O2vii—Mo3—O3viii | 98.1 (3) | O1—Mo2—O2iii | 92.70 (15) |
O5—Mo3—O3viii | 90.79 (18) | O5ii—Mo2—O2iii | 91.57 (16) |
O4—Mo3—O3viii | 84.17 (17) | O1—Mo2—O2ix | 92.70 (15) |
O3iv—Mo3—O3viii | 74.0 (4) | O5ii—Mo2—O2ix | 91.57 (16) |
O2—Mo3—K | 45.19 (17) | O2iii—Mo2—O2ix | 173.4 (3) |
O2vii—Mo3—K | 45.19 (17) | O1—Mo2—O6 | 90.6 (4) |
O5—Mo3—K | 89.3 (2) | O5ii—Mo2—O6 | 173.4 (3) |
O4—Mo3—K | 97.0 (2) | O2iii—Mo2—O6 | 88.11 (16) |
O3iv—Mo3—K | 143.00 (18) | O2ix—Mo2—O6 | 88.11 (16) |
O3viii—Mo3—K | 143.00 (18) | O1—Mo2—O4 | 166.8 (4) |
O6i—Mo1—O6 | 180.000 (1) | O5ii—Mo2—O4 | 97.2 (3) |
O6i—Mo1—O4i | 81.6 (3) | O2iii—Mo2—O4 | 86.94 (15) |
O6—Mo1—O4i | 98.4 (3) | O2ix—Mo2—O4 | 86.94 (15) |
O6i—Mo1—O4 | 98.4 (3) | O6—Mo2—O4 | 76.2 (3) |
O6—Mo1—O4 | 81.6 (3) |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x, −y+1, −z+1; (iii) −x+1/2, −y+1/2, −z+1; (iv) x+1/2, y+1/2, z; (v) −x, −y, z+1/2; (vi) x, y, −z+3/2; (vii) −x, y, z; (viii) −x−1/2, −y+1/2, −z+1; (ix) x−1/2, −y+1/2, −z+1. |
KNb1.76Sb3.24O13 | F(000) = 1441.5 |
Mr = 804.67 | Dx = 5.186 Mg m−3 |
Orthorhombic, Cmcm | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: -C 2c 2 | Cell parameters from 25 reflections |
a = 6.697 (1) Å | θ = 10.0–14.5° |
b = 9.027 (1) Å | µ = 10.74 mm−1 |
c = 17.047 (2) Å | T = 293 K |
V = 1030.6 (2) Å3 | Parallelepiped, colourless |
Z = 4 | 0.20 × 0.05 × 0.04 mm |
Enraf-Nonius CAD-4 diffractometer | 743 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | θmax = 29.9°, θmin = 2.4° |
Graphite monochromator | h = −9→0 |
ω/2θ scans | k = 0→12 |
Absorption correction: ψ scan (North et al., 1968) | l = −23→0 |
Tmin = 0.567, Tmax = 0.643 | 2 standard reflections every 120 min |
832 measured reflections | intensity decay: 0.5% |
832 independent reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.023 | w = 1/[σ2(Fo2) + (0.0389P)2 + 3.9495P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.072 | (Δ/σ)max < 0.001 |
S = 1.18 | Δρmax = 1.34 e Å−3 |
832 reflections | Δρmin = −1.53 e Å−3 |
66 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
2 restraints | Extinction coefficient: 0.00129 (12) |
KNb1.76Sb3.24O13 | V = 1030.6 (2) Å3 |
Mr = 804.67 | Z = 4 |
Orthorhombic, Cmcm | Mo Kα radiation |
a = 6.697 (1) Å | µ = 10.74 mm−1 |
b = 9.027 (1) Å | T = 293 K |
c = 17.047 (2) Å | 0.20 × 0.05 × 0.04 mm |
Enraf-Nonius CAD-4 diffractometer | 832 independent reflections |
Absorption correction: ψ scan (North et al., 1968) | 743 reflections with I > 2σ(I) |
Tmin = 0.567, Tmax = 0.643 | 2 standard reflections every 120 min |
832 measured reflections | intensity decay: 0.5% |
R[F2 > 2σ(F2)] = 0.023 | 66 parameters |
wR(F2) = 0.072 | 2 restraints |
S = 1.18 | Δρmax = 1.34 e Å−3 |
832 reflections | Δρmin = −1.53 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Sb1 | 0.0000 | 0.0000 | 0.5000 | 0.01077 (19) | |
Nb2 | 0.0000 | 0.230 (4) | 0.359 (4) | 0.0131 (12) | 0.44 (4) |
Sb2 | 0.0000 | 0.227 (2) | 0.364 (2) | 0.0131 (12) | 0.56 (3) |
Nb3 | 0.0000 | 0.3735 (14) | 0.5748 (12) | 0.0102 (6) | 0.44 (3) |
Sb3 | 0.0000 | 0.3911 (11) | 0.5762 (7) | 0.0102 (6) | 0.56 (3) |
K | 0.0000 | 0.1318 (2) | 0.7500 | 0.0264 (5) | |
O1 | 0.0000 | 0.1933 (6) | 0.2500 | 0.0120 (11) | |
O2 | 0.2051 (4) | 0.2846 (3) | 0.63116 (15) | 0.0112 (5) | |
O3 | −0.3078 (6) | 0.0000 | 0.5000 | 0.0096 (7) | |
O4 | 0.0000 | 0.2240 (4) | 0.4895 (2) | 0.0099 (8) | |
O5 | 0.0000 | 0.5611 (4) | 0.6419 (2) | 0.0119 (8) | |
O6 | 0.0000 | 0.0126 (4) | 0.3873 (2) | 0.0082 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Sb1 | 0.0109 (3) | 0.0106 (3) | 0.0108 (3) | 0.000 | 0.000 | 0.00117 (16) |
Nb2 | 0.0155 (2) | 0.0081 (7) | 0.016 (4) | 0.000 | 0.000 | 0.0012 (12) |
Sb2 | 0.0155 (2) | 0.0081 (7) | 0.016 (4) | 0.000 | 0.000 | 0.0012 (12) |
Nb3 | 0.0107 (3) | 0.0040 (18) | 0.0158 (4) | 0.000 | 0.000 | −0.0022 (12) |
Sb3 | 0.0107 (3) | 0.0040 (18) | 0.0158 (4) | 0.000 | 0.000 | −0.0022 (12) |
K | 0.0516 (14) | 0.0160 (8) | 0.0115 (8) | 0.000 | 0.000 | 0.000 |
O1 | 0.014 (3) | 0.010 (2) | 0.013 (3) | 0.000 | 0.000 | 0.000 |
O2 | 0.0089 (12) | 0.0106 (11) | 0.0140 (12) | 0.0002 (10) | −0.0004 (10) | 0.0010 (9) |
O3 | 0.0071 (17) | 0.0101 (15) | 0.0115 (17) | 0.000 | 0.000 | 0.0027 (12) |
O4 | 0.0137 (19) | 0.0089 (18) | 0.0071 (16) | 0.000 | 0.000 | 0.0002 (13) |
O5 | 0.020 (2) | 0.0033 (16) | 0.0126 (17) | 0.000 | 0.000 | −0.0003 (13) |
O6 | 0.0135 (18) | 0.0051 (16) | 0.0062 (16) | 0.000 | 0.000 | 0.0016 (12) |
Sb1—O6 | 1.924 (4) | Sb2—O4 | 2.14 (3) |
Sb1—O4i | 2.030 (4) | Nb3—O2iv | 1.858 (12) |
Sb1—O3 | 2.061 (4) | Nb3—O4 | 1.984 (17) |
Nb2—O1 | 1.89 (6) | Nb3—O5 | 2.044 (15) |
Nb2—O5ii | 1.89 (4) | Nb3—O3v | 2.142 (14) |
Nb2—O2iii | 1.987 (6) | Sb3—O5 | 1.900 (11) |
Nb2—O6 | 2.02 (4) | Sb3—O2iv | 1.921 (8) |
Nb2—O4 | 2.22 (6) | Sb3—O3v | 2.076 (9) |
Sb2—O5ii | 1.92 (2) | Sb3—O4 | 2.112 (11) |
Sb2—O1 | 1.96 (3) | K—O6i | 2.679 (4) |
Sb2—O6 | 1.98 (2) | K—O2vi | 2.810 (3) |
Sb2—O2iii | 1.980 (3) | K—O1i | 2.935 (6) |
O6—Sb1—O6i | 180.0 | O5ii—Nb2—O2viii | 93.8 (11) |
O6—Sb1—O4i | 98.46 (15) | O2iii—Nb2—O2viii | 168 (3) |
O6i—Sb1—O4i | 81.54 (15) | O1—Nb2—O6 | 94 (2) |
O6—Sb1—O4 | 81.54 (15) | O5ii—Nb2—O6 | 167 (4) |
O6i—Sb1—O4 | 98.46 (15) | O2iii—Nb2—O6 | 85.2 (11) |
O4i—Sb1—O4 | 180.0 | O2viii—Nb2—O6 | 85.2 (11) |
O6—Sb1—O3 | 90.000 (1) | O1—Nb2—O4 | 169 (2) |
O6i—Sb1—O3 | 90.000 (1) | O5ii—Nb2—O4 | 92 (2) |
O4i—Sb1—O3 | 90.000 (1) | O2iii—Nb2—O4 | 85.1 (17) |
O4—Sb1—O3 | 90.0 | O2viii—Nb2—O4 | 85.1 (17) |
O6—Sb1—O3i | 90.000 (1) | O6—Nb2—O4 | 74.8 (17) |
O6i—Sb1—O3i | 90.000 (1) | O5ii—Sb2—O1 | 96.0 (13) |
O4i—Sb1—O3i | 90.0 | O5ii—Sb2—O6 | 171 (2) |
O4—Sb1—O3i | 90.000 (1) | O1—Sb2—O6 | 92.8 (12) |
O3—Sb1—O3i | 180.0 | O5ii—Sb2—O2iii | 93.2 (6) |
O2iv—Nb3—O4 | 94.9 (5) | O1—Sb2—O2iii | 92.0 (10) |
O2—Nb3—O4 | 94.9 (5) | O6—Sb2—O2iii | 86.5 (6) |
O2iv—Nb3—O5 | 93.9 (7) | O5ii—Sb2—O2viii | 93.2 (6) |
O2—Nb3—O5 | 93.9 (7) | O1—Sb2—O2viii | 92.0 (10) |
O4—Nb3—O5 | 166.9 (10) | O6—Sb2—O2viii | 86.5 (6) |
O2iv—Nb3—O3v | 95.38 (17) | O2iii—Sb2—O2viii | 172.1 (15) |
O2—Nb3—O3v | 169.2 (7) | O5ii—Sb2—O4 | 93.6 (13) |
O4—Nb3—O3v | 85.8 (7) | O1—Sb2—O4 | 170.4 (12) |
O5—Nb3—O3v | 83.8 (4) | O6—Sb2—O4 | 77.6 (10) |
O2iv—Nb3—O3vii | 169.2 (7) | O2iii—Sb2—O4 | 87.5 (10) |
O2—Nb3—O3vii | 95.38 (17) | O2viii—Sb2—O4 | 87.5 (10) |
O4—Nb3—O3vii | 85.8 (7) | O6i—K—O6ix | 121.80 (17) |
O5—Nb3—O3vii | 83.8 (4) | O6i—K—O2vi | 150.33 (6) |
O3v—Nb3—O3vii | 73.9 (6) | O6ix—K—O2vi | 66.97 (8) |
O5—Sb3—O2iv | 96.7 (4) | O6i—K—O2x | 150.33 (6) |
O5—Sb3—O2 | 96.7 (4) | O6ix—K—O2x | 66.97 (8) |
O2iv—Sb3—O2 | 91.3 (5) | O2vi—K—O2x | 58.52 (11) |
O5—Sb3—O3v | 89.2 (4) | O6i—K—O2iv | 66.97 (8) |
O2iv—Sb3—O3v | 95.67 (14) | O6ix—K—O2iv | 150.33 (6) |
O2—Sb3—O3v | 170.3 (5) | O2vi—K—O2iv | 121.18 (13) |
O5—Sb3—O3vii | 89.2 (4) | O2x—K—O2iv | 92.28 (11) |
O2iv—Sb3—O3vii | 170.3 (5) | O6i—K—O2 | 66.97 (8) |
O2—Sb3—O3vii | 95.67 (14) | O6ix—K—O2 | 150.33 (6) |
O3v—Sb3—O3vii | 76.6 (4) | O2vi—K—O2 | 92.28 (12) |
O5—Sb3—O4 | 171.7 (6) | O2x—K—O2 | 121.18 (13) |
O2iv—Sb3—O4 | 89.1 (4) | O2iv—K—O2 | 58.52 (11) |
O2—Sb3—O4 | 89.1 (4) | O6i—K—O1i | 60.90 (9) |
O3v—Sb3—O4 | 84.3 (4) | O6ix—K—O1i | 60.90 (9) |
O3vii—Sb3—O4 | 84.3 (4) | O2vi—K—O1i | 119.41 (6) |
O1—Nb2—O5ii | 100 (2) | O2x—K—O1i | 119.41 (7) |
O1—Nb2—O2iii | 94.1 (17) | O2iv—K—O1i | 119.41 (7) |
O5ii—Nb2—O2iii | 93.8 (11) | O2—K—O1i | 119.41 (6) |
O1—Nb2—O2viii | 94.1 (17) |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x, −y+1, −z+1; (iii) x−1/2, −y+1/2, −z+1; (iv) −x, y, z; (v) −x−1/2, −y+1/2, −z+1; (vi) x, y, −z+3/2; (vii) x+1/2, y+1/2, z; (viii) −x+1/2, −y+1/2, −z+1; (ix) −x, −y, z+1/2; (x) −x, y, −z+3/2. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | KMo5O13 | KNb1.76Sb3.24O13 |
Mr | 726.79 | 804.67 |
Crystal system, space group | Orthorhombic, Cmcm | Orthorhombic, Cmcm |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 6.6027 (10), 8.9552 (10), 16.844 (2) | 6.697 (1), 9.027 (1), 17.047 (2) |
V (Å3) | 996.0 (2) | 1030.6 (2) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 6.62 | 10.74 |
Crystal size (mm) | 0.09 × 0.07 × 0.02 | 0.20 × 0.05 × 0.04 |
Data collection | ||
Diffractometer | Enraf-Nonius CAD-4 diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.601, 0.910 | 0.567, 0.643 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2790, 812, 740 | 832, 832, 743 |
Rint | 0.008 | ? |
(sin θ/λ)max (Å−1) | 0.703 | 0.702 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.100, 1.22 | 0.023, 0.072, 1.18 |
No. of reflections | 812 | 832 |
No. of parameters | 58 | 66 |
No. of restraints | 0 | 2 |
w = 1/[σ2(Fo2) + (0.0499P)2 + 28.8946P] where P = (Fo2 + 2Fc2)/3 | w = 1/[σ2(Fo2) + (0.0389P)2 + 3.9495P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 1.94, −2.48 | 1.34, −1.53 |
Computer programs: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992), CAD-4 EXPRESS and WinGX (Farrugia, 1999), MolEN (Fair, 1990), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 1998), SHELXL97.
Mo1—O6i | 1.909 (7) | Mo2—O4 | 2.174 (8) |
Mo1—O4i | 2.026 (7) | Mo3—O2 | 1.917 (5) |
Mo1—O3i | 2.054 (8) | Mo3—O5 | 1.937 (8) |
Mo1—Mo2i | 3.1198 (7) | Mo3—O4 | 2.046 (8) |
Mo2—O1 | 1.921 (3) | Mo3—O3iv | 2.073 (5) |
Mo2—O5ii | 1.934 (7) | K—O6v | 2.636 (7) |
Mo2—O2iii | 1.961 (6) | K—O2vi | 2.727 (6) |
Mo2—O6 | 1.989 (7) | K—O1i | 2.826 (12) |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x, −y+1, −z+1; (iii) −x+1/2, −y+1/2, −z+1; (iv) x+1/2, y+1/2, z; (v) −x, −y, z+1/2; (vi) x, y, −z+3/2. |
Sb1—O6 | 1.924 (4) | Sb2—O4 | 2.14 (3) |
Sb1—O4i | 2.030 (4) | Nb3—O2iv | 1.858 (12) |
Sb1—O3 | 2.061 (4) | Nb3—O4 | 1.984 (17) |
Nb2—O1 | 1.89 (6) | Nb3—O5 | 2.044 (15) |
Nb2—O5ii | 1.89 (4) | Nb3—O3v | 2.142 (14) |
Nb2—O2iii | 1.987 (6) | Sb3—O5 | 1.900 (11) |
Nb2—O6 | 2.02 (4) | Sb3—O2iv | 1.921 (8) |
Nb2—O4 | 2.22 (6) | Sb3—O3v | 2.076 (9) |
Sb2—O5ii | 1.92 (2) | Sb3—O4 | 2.112 (11) |
Sb2—O1 | 1.96 (3) | K—O6i | 2.679 (4) |
Sb2—O6 | 1.98 (2) | K—O2vi | 2.810 (3) |
Sb2—O2iii | 1.980 (3) | K—O1i | 2.935 (6) |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x, −y+1, −z+1; (iii) x−1/2, −y+1/2, −z+1; (iv) −x, y, z; (v) −x−1/2, −y+1/2, −z+1; (vi) x, y, −z+3/2. |
KMo5O13 crystallizes in the orthorhombic space group Cmcm and is isotypic with KSb5O13 (Bodenstein et al., 1983). The structure possesses a three-dimensional network, which can be described by the succession of MoO6 octahedra sharing edges to form [Mo2Mo1Mo2]O9 triplets. These triplets are associated by sharing O1 corners, yielding zigzag chains running along the [001] direction. These chains are, in turn, associated by sharing axial oxygen corners, with pairs of Mo32O6 octahedra sharing edges to form layers parallel to the (100) plane (Fig. 1).
In the [100] direction, these layers are associated with an ABA ordering. Each Mo32O6 pair of one layer links two [Mo2Mo1Mo2]O9 triplets of the two neighbouring layers by sharing each of its three equatorial oxygen corners with the axial corners of each triplet.
This arrangement of octahedra generates interconnected tunnels, parallel to the [110] and [110] directions, in which the K+ ions are located (Fig. 2).
In the structure of KMo5O13, all Mo—O bond distances are similar to those customarily encountered with MoV and O. However, we note the existence of longer bond distances for Mo1—O4, Mo2—O4 and Mo3—O4 (Table 1) that can be explained by the sharing of atom O4 with the three Mo atoms (Mo1, Mo2 and Mo3). This makes the interaction between the metal atoms and the O atom weaker. The K+ ions are coordinated by seven O atoms.
The crystal structure of KNb1.76Sb3.24O13 is isomorphous with that of KMo5O13. The characteristic feature of this structure is the double occupancy of sites 2 and 3 by Sb and Nb atoms; the occupancies of the Sb and Nb atoms in both sites are 0.56 and 0.44, respectively.
For both compounds, atom O2 lies on a general position, atom O3 lies on a twofold axis, K and O1 have mm symmetry, Mo1 and Sb1 have 2/m symmetry and all other atoms have m symmetry.