research papers
The crystal structure and electron density in sodium vanadium oxide bronze, β-NaxV2O5 [x = 0.282 (3)], have been studied by accurate Mo Kα X-ray diffraction measurements at 9.6 (3) K. No noticeable difference in the crystal structures at room temperature and 9.6 K has been observed. No superstructure reflections, previously found by Kanai, Kagoshima & Nagasawa [(1982), J. Phys. Soc. Jpn, 51, 697–698], have been detected at low temperature. Analysis of the deformation electron density has revealed the presence of the quasi-two-dimensional sheets of the —V—O—V—O— bonds in the structure. The electron density in the different chemical bonds within each of the three crystallographically independent VO6 polyhedra noticeably varies, although there is no clear evidence that the three crystallographically independent V atoms have different valence states.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768101002038/av0034sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108768101002038/av0034NaV2O5sup2.hkl |
Computing details top
Program(s) used to refine structure: Koritsanszky et al., (1995); molecular graphics: Koritsanszky et al., (1995); software used to prepare material for publication: Koritsanszky et al., (1995).
(NaV2O5) top
Crystal data top
Na0.282V2O5 | Dx = 3.594 Mg m−3 |
Mr = 188.36 | Mo Kα radiation, λ = 0.71069 Å |
Monoclinic, C2/m | Cell parameters from 12 reflections |
a = 15.3500 (1) Å | θ = 37.8–39.1° |
b = 3.6115 (4) Å | µ = 5.25 mm−1 |
c = 10.058 (1) Å | T = 10 K |
β = 109.560 (7)° | , black |
V = 525.40 (9) Å3 | 0.21 × 0.14 × 0.05 mm |
Z = 6 |
Data collection top
Huber 512 diffractometer | Rint = 0.028 |
ω–2θ scans | θmax = 50° |
Absorption correction: analytical ? | h = −32→32 |
Tmin = 0.473, Tmax = 0.776 | k = −7→7 |
10461 measured reflections | l = −21→21 |
2938 independent reflections | 3 standard reflections every 100 reflections |
2897 reflections with I > 2/σ(I) | intensity decay: 2% |
Refinement top
Refinement on F | 253 parameters |
R[F2 > 2σ(F2)] = 0.016 | w = 1/σ2(F) |
wR(F2) = 0.0110 | |
2897 reflections | Extinction correction: Becker & Coppens |
Crystal data top
Na0.282V2O5 | V = 525.40 (9) Å3 |
Mr = 188.36 | Z = 6 |
Monoclinic, C2/m | Mo Kα radiation |
a = 15.3500 (1) Å | µ = 5.25 mm−1 |
b = 3.6115 (4) Å | T = 10 K |
c = 10.058 (1) Å | 0.21 × 0.14 × 0.05 mm |
β = 109.560 (7)° |
Data collection top
Huber 512 diffractometer | 2897 reflections with I > 2/σ(I) |
Absorption correction: analytical ? | Rint = 0.028 |
Tmin = 0.473, Tmax = 0.776 | 3 standard reflections every 100 reflections |
10461 measured reflections | intensity decay: 2% |
2938 independent reflections |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | ||
V(1) | 0.337844 (7) | 0.000000 | 0.100038 (11) | 0.004 | |
V(2) | 0.116550 (8) | 0.000000 | 0.119918 (12) | 0.005 | |
V(3) | 0.288107 (8) | 0.000000 | 0.409916 (12) | 0.004 | |
Na(1) | 0.00100 (5) | 0.00000 | 0.40311 (8) | 0.007 | |
O(1) | 0.00000 | 0.00000 | 0.00000 | 0.007 | |
O(2) | 0.18561 (4) | 0.00000 | −0.05486 (5) | 0.007 | |
O(3) | 0.36577 (3) | 0.00000 | −0.07900 (5) | 0.006 | |
O(4) | 0.43750 (4) | 0.00000 | 0.21868 (6) | 0.009 | |
O(5) | 0.26336 (4) | 0.00000 | 0.22320 (5) | 0.006 | |
O(6) | 0.10644 (4) | 0.00000 | 0.27384 (6) | 0.007 | |
O(7) | 0.24317 (3) | 0.00000 | 0.57449 (5) | 0.006 | |
O(8) | 0.39856 (4) | 0.00000 | 0.47136 (5) | 0.008 |
Atomic displacement parameters (Å2) top
U11 | U22 | U33 | U12 | U13 | U23 | |
V(1) | 0.00436 (3) | 0.00401 (4) | 0.00423 (3) | 0.00000 | 0.00158 (3) | 0.00000 |
V(2) | 0.00713 (4) | 0.00393 (4) | 0.00506 (4) | 0.00000 | 0.00310 (3) | 0.00000 |
V(3) | 0.00480 (4) | 0.00405 (4) | 0.00422 (3) | 0.00000 | 0.00199 (3) | 0.00000 |
Na(1) | 0.0074 (2) | 0.0066 (3) | 0.0073 (2) | 0.0000 | 0.0022 (2) | 0.0000 |
O(1) | 0.0050 (2) | 0.0066 (2) | 0.0085 (2) | 0.0000 | 0.0007 (2) | 0.0000 |
O(2) | 0.0077 (2) | 0.0048 (2) | 0.0068 (2) | 0.0000 | 0.0027 (1) | 0.0000 |
O(3) | 0.0066 (2) | 0.0045 (2) | 0.0053 (1) | 0.0000 | 0.0023 (1) | 0.0000 |
O(4) | 0.0055 (2) | 0.0149 (2) | 0.0063 (2) | 0.0000 | 0.0011 (1) | 0.0000 |
O(5) | 0.0055 (1) | 0.0063 (2) | 0.0046 (1) | 0.0000 | 0.0020 (1) | 0.0000 |
O(6) | 0.0077 (2) | 0.0077 (2) | 0.0054 (2) | 0.0000 | 0.0028 (1) | 0.0000 |
O(7) | 0.0087 (2) | 0.0040 (2) | 0.0064 (1) | 0.0000 | 0.0039 (1) | 0.0000 |
O(8) | 0.0056 (2) | 0.0118 (2) | 0.0069 (2) | 0.0000 | 0.0017 (1) | 0.0000 |
Bond lengths (Å) top
V(1)—O(2)i | 1.8674 (1) | V(2)—O(3)iii | 1.8917 (2) |
V(1)—O(2)ii | 1.8674 (1) | V(2)—O(3)iv | 1.8917 (1) |
V(1)—O(2)iii | 1.8674 (1) | V(2)—O(6) | 1.6067 (5) |
V(1)—O(2)iv | 1.8674 (1) | V(2)—O(6)v | 1.6067 (5) |
V(1)—O(4) | 1.5942 (5) | V(3)—O(5) | 1.7871 (5) |
V(1)—O(4)v | 1.5942 (5) | V(3)—O(5)v | 1.7871 (5) |
V(1)—O(5) | 1.9467 (5) | V(3)—O(7)viii | 1.8885 (2) |
V(1)—O(5)v | 1.9467 (5) | V(3)—O(7)ix | 1.8885 (2) |
V(2)—O(1) | 1.7918 (1) | V(3)—O(7)x | 1.8885 (2) |
V(2)—O(1)vi | 1.7918 (1) | V(3)—O(7)xi | 1.8885 (2) |
V(2)—O(1)vii | 1.7918 (1) | V(3)—O(8) | 1.5985 (5) |
V(2)—O(1)v | 1.7918 (1) | V(3)—O(8)v | 1.5985 (5) |
V(2)—O(3)i | 1.8917 (2) | Na(1)—Na(1)xii | 1.9596 (14) |
V(2)—O(3)ii | 1.8917 (1) | Na(1)—Na(1)xiii | 1.9596 (14) |
Symmetry codes: (i) −x+1/2, −y−1/2, −z; (ii) −x+1/2, −y+1/2, −z; (iii) −x+1/2, y−1/2, −z; (iv) −x+1/2, y+1/2, −z; (v) x, −y, z; (vi) −x, y, −z; (vii) −x, −y, −z; (viii) −x+1/2, −y−1/2, −z+1; (ix) −x+1/2, −y+1/2, −z+1; (x) −x+1/2, y−1/2, −z+1; (xi) −x+1/2, y+1/2, −z+1; (xii) −x, y, −z+1; (xiii) −x, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | Na0.282V2O5 |
Mr | 188.36 |
Crystal system, space group | Monoclinic, C2/m |
Temperature (K) | 10 |
a, b, c (Å) | 15.3500 (1), 3.6115 (4), 10.058 (1) |
β (°) | 109.560 (7) |
V (Å3) | 525.40 (9) |
Z | 6 |
Radiation type | Mo Kα |
µ (mm−1) | 5.25 |
Crystal size (mm) | 0.21 × 0.14 × 0.05 |
Data collection | |
Diffractometer | Huber 512 diffractometer |
Absorption correction | Analytical |
Tmin, Tmax | 0.473, 0.776 |
No. of measured, independent and observed [I > 2/σ(I)] reflections | 10461, 2938, 2897 |
Rint | 0.028 |
(sin θ/λ)max (Å−1) | 1.078 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.016, 0.0110, ? |
No. of reflections | 2897 |
No. of parameters | 253 |
No. of restraints | ? |
Δρmax, Δρmin (e Å−3) | ?, ? |
Computer programs: Koritsanszky et al., (1995).
Selected bond lengths (Å) top
V(1)—O(2)i | 1.8674 (1) | V(2)—O(3)iii | 1.8917 (2) |
V(1)—O(2)ii | 1.8674 (1) | V(2)—O(3)iv | 1.8917 (1) |
V(1)—O(2)iii | 1.8674 (1) | V(2)—O(6) | 1.6067 (5) |
V(1)—O(2)iv | 1.8674 (1) | V(2)—O(6)v | 1.6067 (5) |
V(1)—O(4) | 1.5942 (5) | V(3)—O(5) | 1.7871 (5) |
V(1)—O(4)v | 1.5942 (5) | V(3)—O(5)v | 1.7871 (5) |
V(1)—O(5) | 1.9467 (5) | V(3)—O(7)viii | 1.8885 (2) |
V(1)—O(5)v | 1.9467 (5) | V(3)—O(7)ix | 1.8885 (2) |
V(2)—O(1) | 1.7918 (1) | V(3)—O(7)x | 1.8885 (2) |
V(2)—O(1)vi | 1.7918 (1) | V(3)—O(7)xi | 1.8885 (2) |
V(2)—O(1)vii | 1.7918 (1) | V(3)—O(8) | 1.5985 (5) |
V(2)—O(1)v | 1.7918 (1) | V(3)—O(8)v | 1.5985 (5) |
V(2)—O(3)i | 1.8917 (2) | Na(1)—Na(1)xii | 1.9596 (14) |
V(2)—O(3)ii | 1.8917 (1) | Na(1)—Na(1)xiii | 1.9596 (14) |
Symmetry codes: (i) −x+1/2, −y−1/2, −z; (ii) −x+1/2, −y+1/2, −z; (iii) −x+1/2, y−1/2, −z; (iv) −x+1/2, y+1/2, −z; (v) x, −y, z; (vi) −x, y, −z; (vii) −x, −y, −z; (viii) −x+1/2, −y−1/2, −z+1; (ix) −x+1/2, −y+1/2, −z+1; (x) −x+1/2, y−1/2, −z+1; (xi) −x+1/2, y+1/2, −z+1; (xii) −x, y, −z+1; (xiii) −x, −y, −z+1. |