Acta Cryst. (2009). E65, i12 [ doi:10.1107/S1600536809002967 ]
Single crystals of caesium tantalate(V), Cs10Ta29.27O78, were obtained as a serendipitous product in a welded tantalum ampoule by a blank reaction of CsBr and bismuth subnitrate [Bi5O(OH)9(NO3)4] with the container material. The crystal structure of the title compound is made up of a three-dimensional framework constituted by two types of layers, viz. (Ta6O15)n and (Ta3O9)n, parallel to (001), which are linked together by TaO6 octahedra (3m. symmetry) along [001]. This framework has cavities where three independent Cs+ ions (3m. and 
m2 symmetry, respectively) are located. The compound reveals a Ta deficiency at one trigonal prismatic coordinated site (m2 symmetry). The composition of the title compound was verified by energy-dispersive X-ray analysis of single crystals.
The title compound was obtained as a serendipitious product by the reaction of CsBr and bismuth subnitrate (Bi5O(OH)9(NO3)4, 98%, Sigma-Aldrich) with the tantalum container material. It was synthesized under argon at temperatures of 1523 K in a welded tantalum ampoule. The air stable title compound crystallizes in brown rods. The chemical composition of the single-crystal was confirmed by energy-dispersive X-ray (EDX) analysis which revealed no impurity elements.
The site occupation factor (s.o.f.) of the Ta-deficient Ta4 site was refined freely. The maximum residual electron density lies 0.95 Å from O1 and the minimum residual electron density lies at the position of the Cs1 atom.
Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-AREA (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
![[Figure 1]](./wm2217fig1thm.gif)
| Fig. 1. View along [001] on the (Ta6O15)n layer. |
![[Figure 2]](./wm2217fig2thm.gif)
| Fig. 2. View along [001] on the (Ta3O9)n layer. |
![[Figure 3]](./wm2217fig3thm.gif)
| Fig. 3. View along [010] on the layers of the title compound connected via TaO6 octahedra. Displacement ellipsoids are drawn at the 50% probability level. |
| Cs10Ta29.27O78 | Dx = 7.352 Mg m−3 |
| Mr = 7873.51 | Mo Kα radiation, λ = 0.71073 Å |
| Hexagonal, P63/mmc | Cell parameters from 1275 reflections |
| Hall symbol: -P 6c 2c | θ = 2.6–31.6° |
| a = 7.5170 (11) Å | µ = 49.96 mm−1 |
| c = 36.340 (7) Å | T = 294 K |
| V = 1778.3 (5) Å3 | Rod, brown |
| Z = 1 | 0.03 × 0.02 × 0.01 mm |
| F(000) = 3310.4 |
| Stoe IPDS-I diffractometer | 855 independent reflections |
| Radiation source: fine-focus sealed tube | 587 reflections with I > 2σ(I) |
| graphite | Rint = 0.119 |
| ω scans | θmax = 27.5°, θmin = 3.1° |
| Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1999) | h = −9→9 |
| Tmin = 0.218, Tmax = 0.607 | k = −9→9 |
| 14043 measured reflections | l = −46→46 |
| Refinement on F2 | 0 restraints |
| Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
| R[F2 > 2σ(F2)] = 0.033 | Secondary atom site location: difference Fourier map |
| wR(F2) = 0.083 | w = 1/[σ2(Fo2) + (0.0516P)2] where P = (Fo2 + 2Fc2)/3 |
| S = 0.89 | (Δ/σ)max < 0.001 |
| 855 reflections | Δρmax = 1.54 e Å−3 |
| 67 parameters | Δρmin = −3.28 e Å−3 |
| Cs10Ta29.27O78 | Z = 1 |
| Mr = 7873.51 | Mo Kα radiation |
| Hexagonal, P63/mmc | µ = 49.96 mm−1 |
| a = 7.5170 (11) Å | T = 294 K |
| c = 36.340 (7) Å | 0.03 × 0.02 × 0.01 mm |
| V = 1778.3 (5) Å3 |
| Stoe IPDS-I diffractometer | 855 independent reflections |
| Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1999) | 587 reflections with I > 2σ(I) |
| Tmin = 0.218, Tmax = 0.607 | Rint = 0.119 |
| 14043 measured reflections | θmax = 27.5° |
| R[F2 > 2σ(F2)] = 0.033 | Δρmax = 1.54 e Å−3 |
| wR(F2) = 0.083 | Δρmin = −3.28 e Å−3 |
| S = 0.89 | Absolute structure: ? |
| 855 reflections | Flack parameter: ? |
| 67 parameters | Rogers parameter: ? |
| 0 restraints |
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) | |
| Ta1 | 0.0000 | 0.0000 | 0.11749 (3) | 0.0166 (2) | |
| Ta2 | 0.33551 (10) | 0.16775 (5) | 0.034126 (15) | 0.01525 (19) | |
| Ta3 | 0.17146 (6) | 0.34292 (11) | 0.196383 (17) | 0.0204 (2) | |
| Ta4 | 0.0000 | 0.0000 | 0.2500 | 0.0163 (8) | 0.633 (10) |
| O1 | 0.0814 (19) | 0.5407 (9) | 0.1881 (4) | 0.021 (2) | |
| O2 | 0.5486 (9) | 0.4514 (9) | 0.0368 (3) | 0.019 (2) | |
| O3 | 0.1256 (9) | 0.2511 (18) | 0.1456 (3) | 0.022 (2) | |
| O4 | 0.2470 (17) | 0.1235 (8) | 0.0825 (3) | 0.017 (2) | |
| O5 | 0.1410 (8) | −0.1410 (8) | 0.0233 (3) | 0.012 (2) | |
| O6 | 0.2379 (18) | 0.1190 (9) | 0.2082 (3) | 0.019 (2) | |
| O7 | 0.1878 (15) | 0.376 (3) | 0.2500 | 0.023 (4) | |
| Cs1 | 0.6667 | 0.3333 | 0.2500 | 0.0337 (6) | |
| Cs2 | 0.3333 | 0.6667 | 0.08755 (7) | 0.0459 (6) | |
| Cs3 | 0.6667 | 0.3333 | 0.13681 (8) | 0.0564 (7) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Ta1 | 0.0158 (3) | 0.0158 (3) | 0.0180 (5) | 0.00791 (16) | 0.000 | 0.000 |
| Ta2 | 0.0141 (3) | 0.0144 (3) | 0.0173 (3) | 0.00703 (15) | −0.0001 (2) | −0.00005 (11) |
| Ta3 | 0.0181 (3) | 0.0217 (4) | 0.0226 (4) | 0.01083 (19) | −0.00299 (13) | −0.0060 (3) |
| Ta4 | 0.0151 (10) | 0.0151 (10) | 0.0188 (13) | 0.0075 (5) | 0.000 | 0.000 |
| O1 | 0.019 (5) | 0.014 (4) | 0.031 (6) | 0.010 (3) | −0.001 (5) | 0.000 (2) |
| O2 | 0.020 (4) | 0.020 (4) | 0.022 (5) | 0.013 (5) | 0.002 (2) | −0.002 (2) |
| O3 | 0.025 (5) | 0.019 (6) | 0.020 (5) | 0.010 (3) | 0.000 (2) | 0.000 (4) |
| O4 | 0.016 (5) | 0.016 (4) | 0.019 (5) | 0.008 (3) | 0.007 (4) | 0.004 (2) |
| O5 | 0.015 (4) | 0.015 (4) | 0.002 (4) | 0.005 (4) | −0.0019 (19) | 0.0019 (19) |
| O6 | 0.016 (5) | 0.013 (4) | 0.028 (6) | 0.008 (3) | 0.000 (4) | 0.000 (2) |
| O7 | 0.021 (6) | 0.038 (11) | 0.015 (7) | 0.019 (5) | 0.000 | 0.000 |
| Cs1 | 0.0317 (9) | 0.0317 (9) | 0.0377 (15) | 0.0159 (5) | 0.000 | 0.000 |
| Cs2 | 0.0443 (8) | 0.0443 (8) | 0.0493 (15) | 0.0221 (4) | 0.000 | 0.000 |
| Cs3 | 0.0626 (11) | 0.0626 (11) | 0.0441 (14) | 0.0313 (6) | 0.000 | 0.000 |
| Ta1—O3 | 1.928 (12) | Ta3—O7 | 1.960 (2) |
| Ta1—O3i | 1.928 (12) | Ta3—O6ii | 2.028 (12) |
| Ta1—O3ii | 1.928 (12) | Ta3—O6 | 2.027 (10) |
| Ta1—O4i | 2.050 (11) | Ta3—Ta4 | 2.9631 (8) |
| Ta1—O4ii | 2.050 (11) | Ta4—O6i | 2.170 (12) |
| Ta1—O4 | 2.050 (11) | Ta4—O6ii | 2.170 (12) |
| Ta2—O4 | 1.850 (11) | Ta4—O6vii | 2.170 (12) |
| Ta2—O2 | 1.925 (7) | Ta4—O6 | 2.170 (12) |
| Ta2—O2iii | 1.925 (8) | Ta4—O6viii | 2.170 (12) |
| Ta2—O5ii | 2.070 (4) | Ta4—O6ix | 2.170 (12) |
| Ta2—O5 | 2.070 (4) | Ta4—O7ii | 2.45 (2) |
| Ta2—O5iv | 2.114 (10) | Ta4—O7 | 2.45 (2) |
| Ta2—Ta2v | 3.3049 (10) | Ta4—O7ix | 2.446 (19) |
| Ta2—Ta2iv | 3.3049 (10) | Ta4—Ta3ii | 2.9631 (8) |
| Ta3—O3 | 1.940 (12) | Ta4—Ta3i | 2.9631 (8) |
| Ta3—O1 | 1.941 (12) | Ta4—Ta3vii | 2.9631 (8) |
| Ta3—O1vi | 1.941 (12) | ||
| O3—Ta1—O3i | 94.5 (5) | O3—Ta3—Ta4 | 113.2 (4) |
| O3—Ta1—O3ii | 94.5 (5) | O1—Ta3—Ta4 | 127.0 (4) |
| O3i—Ta1—O3ii | 94.5 (5) | O1vi—Ta3—Ta4 | 127.0 (4) |
| O3—Ta1—O4i | 173.7 (5) | O7—Ta3—Ta4 | 55.1 (6) |
| O3i—Ta1—O4i | 89.8 (3) | O6ii—Ta3—Ta4 | 47.1 (3) |
| O3ii—Ta1—O4i | 89.8 (3) | O6—Ta3—Ta4 | 47.1 (3) |
| O3—Ta1—O4ii | 89.8 (3) | O6i—Ta4—O6ii | 76.4 (5) |
| O3i—Ta1—O4ii | 173.7 (5) | O6i—Ta4—O6vii | 138.2 (2) |
| O3ii—Ta1—O4ii | 89.8 (3) | O6ii—Ta4—O6vii | 138.2 (2) |
| O4i—Ta1—O4ii | 85.6 (5) | O6i—Ta4—O6 | 76.4 (5) |
| O3—Ta1—O4 | 89.8 (3) | O6ii—Ta4—O6 | 76.4 (5) |
| O3i—Ta1—O4 | 89.8 (3) | O6vii—Ta4—O6 | 88.9 (6) |
| O3ii—Ta1—O4 | 173.7 (5) | O6i—Ta4—O6viii | 138.2 (2) |
| O4i—Ta1—O4 | 85.6 (5) | O6ii—Ta4—O6viii | 88.9 (6) |
| O4ii—Ta1—O4 | 85.6 (5) | O6vii—Ta4—O6viii | 76.4 (5) |
| O4—Ta2—O2 | 100.2 (4) | O6—Ta4—O6viii | 138.2 (2) |
| O4—Ta2—O2iii | 100.2 (4) | O6i—Ta4—O6ix | 88.9 (6) |
| O2—Ta2—O2iii | 87.5 (7) | O6ii—Ta4—O6ix | 138.2 (2) |
| O4—Ta2—O5ii | 89.5 (4) | O6vii—Ta4—O6ix | 76.4 (5) |
| O2—Ta2—O5ii | 85.4 (4) | O6—Ta4—O6ix | 138.2 (2) |
| O2iii—Ta2—O5ii | 168.9 (4) | O6viii—Ta4—O6ix | 76.4 (5) |
| O4—Ta2—O5 | 89.5 (4) | O6i—Ta4—O7ii | 69.09 (12) |
| O2—Ta2—O5 | 168.9 (4) | O6ii—Ta4—O7ii | 69.09 (12) |
| O2iii—Ta2—O5 | 85.4 (4) | O6vii—Ta4—O7ii | 135.5 (3) |
| O5ii—Ta2—O5 | 100.3 (6) | O6—Ta4—O7ii | 135.5 (3) |
| O4—Ta2—O5iv | 152.4 (5) | O6viii—Ta4—O7ii | 69.09 (12) |
| O2—Ta2—O5iv | 99.7 (4) | O6ix—Ta4—O7ii | 69.09 (12) |
| O2iii—Ta2—O5iv | 99.7 (4) | O6i—Ta4—O7 | 135.5 (3) |
| O5ii—Ta2—O5iv | 73.2 (4) | O6ii—Ta4—O7 | 69.09 (12) |
| O5—Ta2—O5iv | 73.2 (4) | O6vii—Ta4—O7 | 69.09 (12) |
| O4—Ta2—Ta2v | 127.6 (2) | O6—Ta4—O7 | 69.09 (12) |
| O2—Ta2—Ta2v | 132.2 (3) | O6viii—Ta4—O7 | 69.09 (12) |
| O2iii—Ta2—Ta2v | 83.1 (3) | O6ix—Ta4—O7 | 135.5 (3) |
| O5ii—Ta2—Ta2v | 95.4 (3) | O7ii—Ta4—O7 | 120.000 (1) |
| O5—Ta2—Ta2v | 38.3 (3) | O6i—Ta4—O7ix | 69.09 (12) |
| O5iv—Ta2—Ta2v | 37.37 (10) | O6ii—Ta4—O7ix | 135.5 (3) |
| O4—Ta2—Ta2iv | 127.6 (2) | O6vii—Ta4—O7ix | 69.09 (12) |
| O2—Ta2—Ta2iv | 83.1 (3) | O6—Ta4—O7ix | 69.09 (12) |
| O2iii—Ta2—Ta2iv | 132.2 (3) | O6viii—Ta4—O7ix | 135.5 (3) |
| O5ii—Ta2—Ta2iv | 38.3 (3) | O6ix—Ta4—O7ix | 69.09 (12) |
| O5—Ta2—Ta2iv | 95.4 (3) | O7ii—Ta4—O7ix | 120.000 (1) |
| O5iv—Ta2—Ta2iv | 37.37 (10) | O7—Ta4—O7ix | 120.000 (2) |
| Ta2v—Ta2—Ta2iv | 69.83 (3) | Ta3ii—Ta4—Ta3vii | 135.741 (10) |
| O3—Ta3—O1 | 93.3 (4) | Ta3i—Ta4—Ta3vii | 135.741 (10) |
| O3—Ta3—O1vi | 93.3 (5) | Ta3—O1—Ta3x | 140.3 (7) |
| O1—Ta3—O1vi | 94.1 (7) | Ta2—O2—Ta2xi | 151.8 (7) |
| O3—Ta3—O7 | 168.3 (7) | Ta1—O3—Ta3 | 139.9 (7) |
| O1—Ta3—O7 | 94.7 (5) | Ta2—O4—Ta1 | 146.5 (7) |
| O1vi—Ta3—O7 | 94.7 (5) | Ta2i—O5—Ta2 | 132.0 (6) |
| O3—Ta3—O6ii | 88.8 (4) | Ta2i—O5—Ta2v | 104.3 (3) |
| O1—Ta3—O6ii | 91.5 (5) | Ta2—O5—Ta2v | 104.3 (3) |
| O1vi—Ta3—O6ii | 173.9 (5) | Ta3i—O6—Ta3 | 145.0 (6) |
| O7—Ta3—O6ii | 82.4 (6) | Ta3i—O6—Ta4 | 89.8 (3) |
| O3—Ta3—O6 | 88.8 (4) | Ta3—O6—Ta4 | 89.8 (3) |
| O1—Ta3—O6 | 173.9 (5) | Ta3—O7—Ta3vii | 167.5 (11) |
| O1vi—Ta3—O6 | 91.5 (5) | Ta3—O7—Ta4 | 83.8 (6) |
| O7—Ta3—O6 | 82.4 (5) | Ta3vii—O7—Ta4 | 83.8 (6) |
| O6ii—Ta3—O6 | 82.9 (6) |
| Symmetry codes: (i) −x+y, −x, z; (ii) −y, x−y, z; (iii) −y+1, x−y, z; (iv) x−y, x, −z; (v) y, −x+y, −z; (vi) −y+1, x−y+1, z; (vii) x, y, −z+1/2; (viii) −y, x−y, −z+1/2; (ix) −x+y, −x, −z+1/2; (x) −x+y, −x+1, z; (xi) −x+y+1, −x+1, z. |
The authors are indebted to Thomas Miller for performing the single-crystal X-ray diffractometry. Financial support by the Fonds der Chemischen Industrie is gratefully acknowledged.
Boulay, D. du, Oono, A. & Ishizawa, N. (2003). Acta Cryst. E59, i86–i88.
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Stoe & Cie (1999). X-SHAPE. Stoe & Cie, Darmstadt, Germany.
Stoe & Cie (2002). X-AREA. Stoe & Cie, Darmstadt, Germany.
The title compound has a three-dimensional framework, constituted by two types of layers, (Ta6O15)n (Fig. 1, green) and (Ta3O9)n (Fig. 2, blue), parallel to (001). These layers are linked together along [001], according to the sequence (Ta6O15)n-TaO6-(Ta3O9)n-(Ta3O9)n-TaO6, by sharing corners of TaO6 octahedra (red, Fig. 3). The tantalum atom with deficient occupation is located in a site with trigonal-prismatic coordinated sites (yellow), between two Ta3O9 units belonging to two neighboring (Ta3O9)n layers. This framework has cavities which communicate with interconnected channels, parallel to [100]. Cs+ ions (black) are located in these cavities. Geometric parameters of the title compound are in the usual ranges. Based on a previous powder diffraction study of Cs10Ta29.27O78 reported by Michel et al. (1978), an additional Ta site was found, but was not observed in the current re-investigation. The closely related structure of Tl10Nb29.2O78 was also reported (Marini et al., 1979) with an additional Nb site with too short interatomic distances between the Nb atoms.
The title compound crystallizes isotypically with Rb5VONb14O38 (Haddad & Jouini, 1997), in which the vanadium atom occupies the trigonal-prismatic Ta deficiency site of the title compound. The related compound Cs3Ta5O14 was first investigated by powder diffraction studies by Serafin & Hoppe (1982) and was later re-investigated on the basis of single-crystal X-ray diffraction by du Boulay et al. (2003). An overview on the related hexagonal tungsten bronzes of potassium, rubidium and caesium was presented by Magnéli (1953).