Barium divanadium(V) tellurite(IV)

A new three-dimensional bimetallic tellurite, BaV₂TeO₈, was synthesized by the hydro­thermal reaction of Ba(OH)₂, TeO₂ and V₂O₅, and characterized by single-crystal X-ray diffraction. The three-dimensional framework is built up from anionic [V₂TeO₈]_n^2n- layers parallel to (101) and connected via Ba-O bonds. The anionic layers are formed by three types of polyhedra, namely VO₅ tetra­gonal pyramids, VO₄ tetra­hedra and TeO₄₊₂ `folded square' polyhedra.

S1. Comment

Both vanadium and tellurium exhibit a variety of coordination geometries, such as the VO₄ tetrahedron, the VO₆ octahedron, the VO₅ square pyramid, the TeO₃ trigonal pyramid, the TeO₄ folded square and the TeO₅ square pyramid, which lead to the rich structural chemistry of vanadium tellurites. A series of compounds have been obtained, such as Te₂V₂O₉ (Darriet & Galy, 1973), TeVO₄ (Meunier et al., 1972), TeVO₄ (Meunier et al., 1973), NaVTeO₅ (Darriet et al., 1972), KVTeO₅ (Darriet et al., 1972), Cs(VO₂)₃(TeO₃)₂ (Harrison & Buttery, 2000), M(phen)V₂TeO₈ (M = Cu and Ni; Xiao, Li et al., 2003), V₄Te₄O₁₈ (Xiao, Wang et al., 2003). Thus, the preparation of novel vanadium tellurites continues to be an intriguing endeavour.

Recently, the hydrothermal method has found broader application in the syntheses of a variety of inorganic oxide materials, such as metal phosphates (Soghomonian et al., 1995), phosphonates (Bonavia et al., 1996) and selenites (Vaughey et al., 1994). The metastable materials thus prepared possess novel low-dimensional or three-dimensional framework structures. We have attempted to introduce the hydrothermal method into the synthesis of vanadium tellurites, in order to obtain compounds with novel structures. In this paper, we report the crystal structure of the new vanadium tellurite, BaV₂TeO₈.

There are two crystallographically independent V atoms, one Te atom and one Ba atom in this structure (Fig. 1). Atom V1 exhibits a distorted tetrahedral coordination geometry, with two terminal O atoms (O1 and O2), and two µ₂-O atoms (O3 and O4) linked to Te atoms. The V1—O bond lengths are in the range 1.651 (3)–1.833 (3) Å, and the O—V1—O angles range from 107.46 (14) to 111.51 (14)°. Atom V2 has square-pyramidal coordination, with two terminal O atoms (O5, O6), one µ₂-O atom (O8) shared with Te, and two µ₃-O atoms (O7 and O7^vi; symmetry codes: (vi) −1 − x, 1 − y, 1 − z] linked with Te and V2^vi [symmetry code: (vi) −1 − x, 1 − y, 1 − z). The V2—O bond lengths are in the range 1.645 (3) − 1.990 (3) Å, and the O—V2—O angles vary from 77.55 (11) to 143.55 (15)°. The Te atom has a folded square coordination geometry, with three µ₂-O atoms (O3, O4 and O8), two of which are shared with V1 atoms and the third bridging atoms Te and V2, and one µ₃-O atom (O7), shared with V2 and V2^vi [symmetry code: (vi) −1 − x, 1 − y, 1 − z]. This geometry can be simply rationalized in VSEPR theory as an AX₄E trigonal bipyramid, with the lone pair of electrons occupying an equatorial position. The Te—O bond lengths range from 1.891 (3) to 2.125 (3) Å, and the two axial bonds are longer than the two equatorial ones. The O—Te—O angles are in the range of 73.77 (11)–152.78 (11)°. Moreover, there are two long Te—O contacts, namely Te—O2 (2.942 Å) and Te—O6 (2.644 Å). The overall shape of this TeO_{4 + 2} group approximates to a distorted octahedron. The Ba atom adopts a nine-coordination mode.

The title compound exhibits a three-dimensional framework. The framework contains two-dimensional [V1V2TeO₈]_n²ⁿ⁻ folded anionic layers (Fig. 2) formed by VO₅ square pyramids, VO₄ tetrahedra and TeO₄ polyhedra, which share corners and edges, with Ba atoms located between the layers. The TeO₄ polyhedra and VO₄ tetrahedra share corners to form an infinite [V1TeO₆]_n chain, parallel to the b axis. Two V2O₅ square pyramids share an edge to form a V2₂O₈ moiety. The V2₂O₈ moieties connect two [V1TeO₆]_n chains into a complex [V1V2TeO₈]_n^2n- band by sharing an edge with neighboring TeO₄ groups. Taking the weak Te—O interaction into account, neighboring [V1V2TeO₈]_n²ⁿ⁻ infinite bands combine with each other to form [V1V2TeO₈]_n²ⁿ⁻ infinite layers parallel to (101). Successive layers are linked by Ba—O interactions into a three-dimensional framework.

S2. Experimental

A mixture of V₂O₅ (0.0455 g), TeO₂ (0.795 g), Ba(OH)₂·8H₂O (0.0947 g) and H₂O (5 ml) was sealed in a 23 ml Teflon-lined stainless steel autoclave. The molar ratio of Ba/V/Te/H₂O was 3:5:5:278. The mixture was heated at 473 K for five days and then cooled to room temperature. Bright yellow block crystals of the title compound were obtained, washed with distilled water and dried at room temperature.

S3. Refinement

Space group P2₁/n was established from the systematic absences. Heavy atoms were located by direct methods, and the remaining atoms were found on successive difference Fourier syntheses. The positional and anisotropic displacement parameters for all atoms (110 parameters) were refined by full-matrix least squares to F².

Computing details

Data collection: TEXRAY (Molecular Structure Corporation, 1999); cell refinement: TEXRAY; data reduction: TEXSAN (Molecular Structure Corporation, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX (McArdle, 1995); software used to prepare material for publication: SHELXL97-2 (Sheldrick,1997).

Figures

	Fig. 1. Coordination enviroments of the V, Te and Ba atoms, showing the atom-labeling scheme and 50% probability displacement ellipsoids.
	Fig. 2. Infinite [V1V2TeO8]n^2n− layers parallel to (101). The light lines represent weak Te—O interactions.

(I)

Crystal data

BaO8TeV2	F(000) = 872
Mr = 494.82	Dx = 4.548 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.6380 (8) Å	Cell parameters from 25 reflections
b = 5.6665 (3) Å	θ = 12–18°
c = 13.8866 (11) Å	µ = 11.88 mm^−1
β = 107.642 (4)°	T = 293 K
V = 722.73 (9) Å^3	Block, yellow
Z = 4	0.30 × 0.15 × 0.05 mm

Data collection

Rigaku Weissenberg IP diffractometer	1663 independent reflections
Radiation source: rotor target	1538 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
ϕ or ω scans?	θmax = 27.5°, θmin = 2.3°
Absorption correction: multi-scan (TEXRAY; Molecular Structure Corporation, 1999)	h = 0→12
Tmin = 0.13, Tmax = 0.55	k = 0→7
1663 measured reflections	l = −18→17

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.017	w = 1/[σ^2(Fo^2) + (0.0236P)^2 + 1.1787P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.056	(Δ/σ)max = 0.001
S = 1.23	Δρmax = 0.79 e Å^−3
1663 reflections	Δρmin = −1.00 e Å^−3
110 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0112 (3)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Ba1	0.09329 (2)	0.18493 (4)	0.344460 (17)	0.01384 (10)
Te1	−0.30304 (3)	0.17884 (4)	0.411192 (17)	0.00905 (10)
V1	−0.15161 (7)	0.66023 (11)	0.36459 (5)	0.00891 (14)
V2	−0.41792 (7)	0.34548 (11)	0.58981 (5)	0.01013 (15)
O1	−0.0087 (3)	0.6793 (5)	0.3230 (2)	0.0156 (6)
O2	−0.3002 (3)	0.6391 (5)	0.2670 (2)	0.0164 (6)
O3	−0.1577 (3)	0.9121 (5)	0.4404 (2)	0.0138 (5)
O4	−0.1352 (3)	0.3864 (5)	0.4375 (2)	0.0134 (5)
O5	−0.3081 (3)	0.5005 (6)	0.6818 (2)	0.0208 (6)
O6	−0.4896 (3)	0.1430 (5)	0.6459 (2)	0.0164 (6)
O7	−0.5863 (3)	0.5369 (5)	0.5443 (2)	0.0194 (6)
O8	−0.2984 (3)	0.1153 (5)	0.5458 (2)	0.0138 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ba1	0.01201 (14)	0.01688 (15)	0.01191 (14)	0.00261 (8)	0.00257 (9)	0.00222 (8)
Te1	0.00858 (14)	0.01016 (15)	0.00872 (14)	0.00019 (8)	0.00307 (9)	0.00072 (8)
V1	0.0093 (3)	0.0087 (3)	0.0096 (3)	0.0000 (2)	0.0042 (2)	−0.0010 (2)
V2	0.0109 (3)	0.0103 (3)	0.0103 (3)	0.0016 (2)	0.0049 (2)	0.0015 (2)
O1	0.0126 (13)	0.0190 (15)	0.0165 (14)	−0.0002 (11)	0.0061 (11)	−0.0009 (11)
O2	0.0133 (13)	0.0190 (14)	0.0153 (13)	0.0003 (12)	0.0023 (11)	0.0003 (12)
O3	0.0158 (13)	0.0118 (13)	0.0130 (12)	0.0044 (11)	0.0029 (10)	−0.0020 (11)
O4	0.0110 (12)	0.0118 (12)	0.0161 (13)	−0.0021 (11)	0.0022 (10)	0.0017 (11)
O5	0.0215 (14)	0.0220 (15)	0.0197 (14)	−0.0065 (13)	0.0073 (11)	−0.0043 (13)
O6	0.0164 (14)	0.0173 (13)	0.0165 (13)	−0.0020 (12)	0.0067 (11)	0.0023 (12)
O7	0.0232 (14)	0.0229 (15)	0.0171 (14)	0.0146 (13)	0.0133 (12)	0.0098 (13)
O8	0.0162 (13)	0.0153 (13)	0.0109 (12)	0.0061 (12)	0.0054 (10)	0.0037 (11)

Geometric parameters (Å, º)

Ba1—O8^i	2.701 (3)	V1—O4	1.833 (3)
Ba1—O2^ii	2.791 (3)	V1—Te1^viii	3.4289 (7)
Ba1—O6^iii	2.802 (3)	V1—Ba1^viii	3.8586 (7)
Ba1—O5^iv	2.838 (3)	V2—O5	1.645 (3)
Ba1—O5^iii	2.900 (3)	V2—O6	1.652 (3)
Ba1—O3^iv	2.914 (3)	V2—O7	1.894 (3)
Ba1—O1	2.954 (3)	V2—O8	1.956 (3)
Ba1—O1^v	3.014 (3)	V2—O7^vi	1.990 (3)
Ba1—O4	3.090 (3)	V2—V2^vi	3.0659 (13)
Ba1—V2^iii	3.5092 (7)	V2—Ba1^ix	3.5092 (7)
Ba1—V1	3.6473 (7)	O1—Ba1^viii	3.014 (3)
Ba1—V1^v	3.8586 (7)	O2—Ba1^x	2.791 (3)
Te1—O8	1.891 (3)	O2—Te1^x	2.942 (3)
Te1—O4	1.943 (3)	O3—Te1^viii	2.017 (3)
Te1—O3^v	2.017 (3)	O3—Ba1^iv	2.914 (3)
Te1—O7^vi	2.125 (3)	O5—Ba1^iv	2.838 (3)
Te1—O6^vii	2.644 (3)	O5—Ba1^ix	2.900 (3)
Te1—O2^ii	2.942 (3)	O6—Te1^vii	2.644 (3)
Te1—V2	3.1519 (7)	O6—Ba1^ix	2.802 (3)
Te1—V1	3.2500 (7)	O7—V2^vi	1.990 (3)
V1—O1	1.651 (3)	O7—Te1^vi	2.125 (3)
V1—O2	1.651 (3)	O8—Ba1^i	2.701 (3)
V1—O3	1.785 (3)
O8^i—Ba1—O2^ii	134.33 (9)	O8—Te1—O2^ii	154.72 (10)
O8^i—Ba1—O6^iii	135.69 (8)	O4—Te1—O2^ii	74.32 (10)
O2^ii—Ba1—O6^iii	63.14 (8)	O3^v—Te1—O2^ii	73.76 (9)
O8^i—Ba1—O5^iv	91.73 (9)	O7^vi—Te1—O2^ii	129.06 (10)
O2^ii—Ba1—O5^iv	129.96 (9)	O6^vii—Te1—O2^ii	96.45 (9)
O6^iii—Ba1—O5^iv	69.92 (9)	O1—V1—O2	109.00 (14)
O8^i—Ba1—O5^iii	81.63 (8)	O1—V1—O3	109.53 (14)
O2^ii—Ba1—O5^iii	92.87 (8)	O2—V1—O3	111.51 (14)
O6^iii—Ba1—O5^iii	54.76 (8)	O1—V1—O4	107.88 (13)
O5^iv—Ba1—O5^iii	72.75 (6)	O2—V1—O4	107.46 (14)
O8^i—Ba1—O3^iv	53.90 (8)	O3—V1—O4	111.35 (13)
O2^ii—Ba1—O3^iv	114.60 (8)	O5—V2—O6	105.50 (15)
O6^iii—Ba1—O3^iv	169.41 (8)	O5—V2—O7	103.76 (15)
O5^iv—Ba1—O3^iv	108.25 (8)	O6—V2—O7	96.69 (14)
O5^iii—Ba1—O3^iv	135.39 (8)	O5—V2—O8	107.31 (14)
O8^i—Ba1—O1	144.92 (8)	O6—V2—O8	93.11 (14)
O2^ii—Ba1—O1	77.43 (9)	O7—V2—O8	143.47 (12)
O6^iii—Ba1—O1	65.41 (8)	O5—V2—O7^vi	110.93 (15)
O5^iv—Ba1—O1	67.96 (9)	O6—V2—O7^vi	143.55 (15)
O5^iii—Ba1—O1	116.27 (8)	O7—V2—O7^vi	75.77 (12)
O3^iv—Ba1—O1	104.09 (8)	O8—V2—O7^vi	75.55 (11)
O8^i—Ba1—O1^v	67.55 (8)	V1—O1—Ba1	100.96 (12)
O2^ii—Ba1—O1^v	67.17 (8)	V1—O1—Ba1^viii	108.00 (12)
O6^iii—Ba1—O1^v	104.25 (8)	Ba1—O1—Ba1^viii	143.42 (11)
O5^iv—Ba1—O1^v	144.38 (8)	V1—O2—Ba1^x	158.21 (15)
O5^iii—Ba1—O1^v	75.67 (8)	V1—O2—Te1^x	104.76 (12)
O3^iv—Ba1—O1^v	83.33 (8)	Ba1^x—O2—Te1^x	94.02 (8)
O1—Ba1—O1^v	143.42 (11)	V1—O3—Te1^viii	128.75 (15)
O8^i—Ba1—O4	119.31 (7)	V1—O3—Ba1^iv	114.77 (12)
O2^ii—Ba1—O4	62.37 (8)	Te1^viii—O3—Ba1^iv	105.47 (10)
O6^iii—Ba1—O4	104.82 (8)	V1—O4—Te1	118.78 (14)
O5^iv—Ba1—O4	117.51 (8)	V1—O4—Ba1	92.01 (10)
O5^iii—Ba1—O4	154.53 (8)	Te1—O4—Ba1	110.87 (11)
O3^iv—Ba1—O4	66.33 (7)	V2—O5—Ba1^iv	123.95 (14)
O1—Ba1—O4	55.55 (7)	V2—O5—Ba1^ix	97.22 (13)
O1^v—Ba1—O4	98.06 (7)	Ba1^iv—O5—Ba1^ix	138.74 (11)
O8—Te1—O4	99.26 (12)	V2—O6—Te1^vii	136.38 (15)
O8—Te1—O3^v	81.47 (11)	V2—O6—Ba1^ix	100.79 (13)
O4—Te1—O3^v	85.88 (11)	Te1^vii—O6—Ba1^ix	119.96 (10)
O8—Te1—O7^vi	73.77 (11)	V2—O7—V2^vi	104.23 (12)
O4—Te1—O7^vi	87.09 (12)	V2—O7—Te1^vi	142.38 (17)
O3^v—Te1—O7^vi	152.78 (11)	V2^vi—O7—Te1^vi	99.93 (12)
O8—Te1—O6^vii	87.39 (11)	Te1—O8—V2	109.99 (13)
O4—Te1—O6^vii	169.92 (10)	Te1—O8—Ba1^i	118.13 (12)
O3^v—Te1—O6^vii	87.65 (11)	V2—O8—Ba1^i	130.04 (12)
O7^vi—Te1—O6^vii	102.11 (11)

Symmetry codes: (i) −x, −y, −z+1; (ii) −x−1/2, y−1/2, −z+1/2; (iii) x+1/2, −y+1/2, z−1/2; (iv) −x, −y+1, −z+1; (v) x, y−1, z; (vi) −x−1, −y+1, −z+1; (vii) −x−1, −y, −z+1; (viii) x, y+1, z; (ix) x−1/2, −y+1/2, z+1/2; (x) −x−1/2, y+1/2, −z+1/2.