β-Nb9VO25.

The title compound, nona-niobium vanadium penta-cosa-oxide, was prepared by a solid-state reaction at 1198 K. It is isotypic with Nb9AsO25, Nb9PO25 and Ta9VO25. The structure consists of NbO6 octa-hedra (one with 4/m.. and two with m.. symmetry) and VO4 tetra-hedra (-4.. symmetry) sharing corners and edges to form a three-dimensional framework. This framework can be considered as a junction between ribbons made up from NbO6 octa-hedra and chains of NbO6 octa-hedra and chains of VO4 tetra-hedra. The V site shows half-occupancy, hence one half of the VO4 tetra-hedra is unoccupied. The structural differences with α-Nb9VO25, VOSO4, SbOPO4 and NbOPO4 oxides are discussed.

Related literature

For isotypic compouds, see: Ulutagay et al. (1998 ▶); Roth et al. (1965 ▶); Casais et al. (1993 ▶). For physical properties, see: Prabaharan et al. (1997 ▶); Aranda et al. (1992 ▶); Bergner et al. (2009 ▶). For details of structurally related compounds, see: Haddad & Jouini (1996 ▶, 1997 ▶); Zid et al. (1992 ▶); Casais et al. (1993 ▶); Chérif et al. (2011 ▶); Roth et al. (1965 ▶); Köhler et al. (1989 ▶); Piffard et al. (1986 ▶); Longo & Arnott (1970 ▶); Tachez et al. (1981 ▶); Amos et al. (1998 ▶). For details of bond-valence calculations, see: Brown & Altermatt (1985 ▶).

Experimental

Crystal data

Nb9VO25

M = 1287.13

Tetragonal,

a = 15.7726 (9) Å

c = 3.8399 (6) Å

V = 955.27 (17) Å3

Z = 2

Mo Kα radiation

μ = 5.78 mm−1

T = 298 K

0.14 × 0.05 × 0.04 mm

Data collection

Enraf–Nonius CAD-4 diffractometer

Absorption correction: ψ scan (North et al., 1968 ▶) T min = 0.695, T max = 0.812

851 measured reflections

593 independent reflections

363 reflections with I > 2σ(I)

R int = 0.044

2 standard reflections every 120 min intensity decay: 1.1%

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.086

S = 0.99

593 reflections

56 parameters

Δρmax = 1.15 e Å−3

Δρmin = −1.52 e Å−3

Data collection: CAD-4 EXPRESS (Duisenberg, 1992 ▶; Macíček & Yordanov, 1992 ▶); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 1999 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S1600536814007831/vn2081sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814007831/vn2081Isup2.hkl

CCDC reference: 996072

Additional supporting information: crystallographic information; 3D view; checkCIF report

Nb9VO25	Dx = 4.475 Mg m−3
Mr = 1287.13	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4/m	Cell parameters from 25 reflections
Hall symbol: -I 4	θ = 11–15°
a = 15.7726 (9) Å	µ = 5.78 mm−1
c = 3.8399 (6) Å	T = 298 K
V = 955.27 (17) Å3	Prism, yellow
Z = 2	0.14 × 0.05 × 0.04 mm
F(000) = 1184

Enraf–Nonius CAD-4 diffractometer	363 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.044
Graphite monochromator	θmax = 26.9°, θmin = 2.6°
ω/2θ scans	h = −20→1
Absorption correction: ψ scan (North et al., 1968)	k = −20→1
Tmin = 0.695, Tmax = 0.812	l = −4→1
851 measured reflections	2 standard reflections every 120 min
593 independent reflections	intensity decay: 1.1%

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)] = 0.034	w = 1/[σ2(Fo2) + (0.0234P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.086	(Δ/σ)max < 0.001
S = 0.99	Δρmax = 1.15 e Å−3
593 reflections	Δρmin = −1.52 e Å−3
56 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 0.0050 (3)

Experimental. Le cristal étant de faible taille, la correction d'absorption par psi-scan n'a pas amélioré le résultat de l'affinement.

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)
Nb1	0.0000	0.0000	0.0000	0.0195 (7)
Nb2	0.78149 (7)	0.10593 (7)	0.0000	0.0058 (4)
Nb3	0.88301 (6)	0.32601 (6)	0.0000	0.0057 (3)
V1	0.0000	0.5000	0.7500	0.0071 (12)	0.50
O1	0.8838 (5)	0.0515 (5)	0.0000	0.012 (2)
O2	0.8233 (5)	0.2169 (5)	0.0000	0.013 (2)
O3	0.7479 (5)	0.1109 (5)	0.5000	0.0084 (19)
O4	0.7185 (5)	−0.0125 (5)	0.0000	0.0106 (19)
O5	0.6482 (5)	0.1572 (5)	0.0000	0.010 (2)
O6	0.0000	0.0000	0.5000	0.020 (5)
O7	0.9251 (5)	0.4473 (5)	0.0000	0.0069 (18)

	U11	U22	U33	U12	U13	U23
Nb1	0.0071 (8)	0.0071 (8)	0.044 (2)	0.000	0.000	0.000
Nb2	0.0044 (5)	0.0083 (6)	0.0048 (7)	−0.0002 (4)	0.000	0.000
Nb3	0.0058 (6)	0.0068 (6)	0.0045 (6)	0.0015 (5)	0.000	0.000
V1	0.0072 (17)	0.0072 (17)	0.007 (3)	0.000	0.000	0.000
O1	0.010 (4)	0.012 (4)	0.012 (5)	0.003 (3)	0.000	0.000
O2	0.018 (4)	0.010 (4)	0.012 (5)	−0.002 (4)	0.000	0.000
O3	0.003 (4)	0.011 (4)	0.012 (5)	−0.003 (4)	0.000	0.000
O4	0.009 (4)	0.007 (4)	0.015 (5)	−0.004 (4)	0.000	0.000
O5	0.010 (4)	0.015 (5)	0.004 (5)	0.005 (4)	0.000	0.000
O6	0.023 (7)	0.023 (7)	0.016 (11)	0.000	0.000	0.000
O7	0.008 (4)	0.007 (4)	0.006 (4)	0.000 (3)	0.000	0.000

Nb1—O6i	1.9200 (3)	Nb3—O7	2.025 (7)
Nb1—O6	1.9200 (3)	Nb3—O3viii	2.292 (8)
Nb1—O1ii	2.005 (8)	V1—O7ix	1.735 (6)
Nb1—O1iii	2.005 (8)	V1—O7x	1.735 (6)
Nb1—O1iv	2.005 (8)	V1—O7xi	1.735 (6)
Nb1—O1v	2.005 (8)	V1—O7xii	1.735 (6)
Nb2—O1	1.827 (8)	O1—Nb1xiii	2.005 (8)
Nb2—O2	1.870 (8)	O3—Nb2xiv	1.993 (2)
Nb2—O3i	1.993 (2)	O3—Nb3viii	2.292 (8)
Nb2—O3	1.993 (2)	O4—Nb3xv	1.792 (7)
Nb2—O4	2.115 (7)	O5—Nb3vii	1.999 (2)
Nb2—O5	2.253 (8)	O5—Nb3viii	1.999 (2)
Nb3—O4vi	1.792 (7)	O6—Nb1xiv	1.9200 (3)
Nb3—O2	1.962 (8)	O7—V1ix	1.735 (6)
Nb3—O5vii	1.999 (2)	O7—V1xvi	1.735 (6)
Nb3—O5viii	1.999 (2)
O6i—Nb1—O6	180.0	O2—Nb3—O7	170.5 (3)
O6i—Nb1—O1ii	90.0	O5vii—Nb3—O7	87.5 (2)
O6—Nb1—O1ii	90.0	O5viii—Nb3—O7	87.5 (2)
O6i—Nb1—O1iii	90.0	O4vi—Nb3—O3viii	177.3 (3)
O6—Nb1—O1iii	90.0	O2—Nb3—O3viii	87.1 (3)
O1ii—Nb1—O1iii	180.0 (5)	O5vii—Nb3—O3viii	73.8 (2)
O6i—Nb1—O1iv	90.0	O5viii—Nb3—O3viii	73.8 (2)
O6—Nb1—O1iv	90.0	O7—Nb3—O3viii	83.4 (3)
O1ii—Nb1—O1iv	90.0	O7ix—V1—O7x	107.83 (13)
O1iii—Nb1—O1iv	90.0	O7ix—V1—O7xi	107.83 (13)
O6i—Nb1—O1v	90.0	O7x—V1—O7xi	112.8 (3)
O6—Nb1—O1v	90.0	O7ix—V1—O7xii	112.8 (3)
O1ii—Nb1—O1v	90.0	O7x—V1—O7xii	107.83 (13)
O1iii—Nb1—O1v	90.0	O7xi—V1—O7xii	107.83 (13)
O1iv—Nb1—O1v	180.0	O7ix—V1—V1xvii	123.60 (13)
O1—Nb2—O2	97.3 (3)	O7x—V1—V1xvii	56.40 (13)
O1—Nb2—O3i	104.7 (2)	O7xi—V1—V1xvii	56.40 (13)
O2—Nb2—O3i	93.3 (2)	O7xii—V1—V1xvii	123.60 (13)
O1—Nb2—O3	104.7 (2)	O7ix—V1—V1xviii	56.40 (13)
O2—Nb2—O3	93.3 (2)	O7x—V1—V1xviii	123.60 (13)
O3i—Nb2—O3	148.8 (4)	O7xi—V1—V1xviii	123.60 (13)
O1—Nb2—O4	90.0 (3)	O7xii—V1—V1xviii	56.40 (13)
O2—Nb2—O4	172.7 (3)	V1xvii—V1—V1xviii	180.0
O3i—Nb2—O4	84.8 (2)	Nb2—O1—Nb1xiii	175.9 (5)
O3—Nb2—O4	84.8 (2)	Nb2—O2—Nb3	172.0 (5)
O1—Nb2—O5	173.0 (3)	Nb2xiv—O3—Nb2	148.8 (4)
O2—Nb2—O5	89.6 (3)	Nb2xiv—O3—Nb3viii	104.9 (2)
O3i—Nb2—O5	74.8 (2)	Nb2—O3—Nb3viii	104.9 (2)
O3—Nb2—O5	74.8 (2)	Nb3xv—O4—Nb2	175.1 (5)
O4—Nb2—O5	83.1 (3)	Nb3vii—O5—Nb3viii	147.6 (4)
O4vi—Nb3—O2	95.6 (3)	Nb3vii—O5—Nb2	106.1 (2)
O4vi—Nb3—O5vii	106.1 (2)	Nb3viii—O5—Nb2	106.1 (2)
O2—Nb3—O5vii	89.9 (2)	Nb1xiv—O6—Nb1	180.0
O4vi—Nb3—O5viii	106.1 (2)	V1ix—O7—V1xvi	67.2 (3)
O2—Nb3—O5viii	89.9 (2)	V1ix—O7—Nb3	132.5 (3)
O5vii—Nb3—O5viii	147.6 (4)	V1xvi—O7—Nb3	132.5 (3)
O4vi—Nb3—O7	94.0 (3)