La variété β-NaMoO(2)(AsO(4)).

The title compound, sodium dioxidomolybdenum(VI) arsenate(V), β-NaMoO(2)AsO(4), was prepared by solid-state reaction at 953 K. In the crystal structure, the AsO(4) tetra-hedra and MoO(6) octa-hedra (both with m symmetry) share corner atoms to form a three-dimensional framework that delimits cavities parallel to [010] where disordered six-coordinated sodium cations (half-occupation) are located. Structural relationships between the different orthoarsenates of the AMoO(2)AsO(4) series (A = Ag, Li, Na, K and Rb) are discussed.

Littérature associée

Pour le contexte général du travail, voir: Brown & Altermatt (1985 ▶); Benhamada et al. (1992 ▶); Haddad et al. (1988 ▶); Harrison et al. (1994 ▶); Ledain et al. (1997 ▶); Piffard et al. (1985 ▶); Zid et al. (1992 ▶). La structure est isotypique avec AgMoO2AsO4 (Hajji & Zid, 2006 ▶) et KMoO2AsO4 (Zid & Jouini, 1996a ▶). Pour structures associées, voir: Hajji et al. (2004 ▶) (β-LiMoO2AsO4); Hajji et al. (2005 ▶) [Li(MoO2)2O(AsO4)]; Linnros (1970 ▶) (LiMoO2AsO4); Zid & Jouini (1996b ▶) (K2MoO2As2O7); Zid & Jouini (1999 ▶) (RbMoO2AsO4); Zid et al. (1997 ▶) (α-NaMoO2AsO4); Zid et al. (1998 ▶) (K2MoO2As2O7).

Partie expérimentale

Données cristallines

NaMoO2(AsO4)

M = 289.85

Orthorhombique,

a = 10.147 (2) Å

b = 6.597 (2) Å

c = 7.420 (2) Å

V = 496.7 (2) Å3

Z = 4

Radiation Mo Kα

μ = 9.29 mm−1

T = 298 (2) K

0.26 × 0.16 × 0.10 mm

Collection des données

Diffractomètre Enraf–Nonius CAD-4

Correction d’absorption: ψ scan (North et al., 1968 ▶) T min = 0.186, T max = 0.394

1438 réflexions mesurées

589 réflexions independantes

539 réflexions avec I > 2σ(I)

R int = 0.027

2 réflexions de référence fréquence: 120 min déclin d’intensité: 1.2%

Affinement

R[F 2 > 2σ(F 2)] = 0.019

wR(F 2) = 0.053

S = 1.14

589 réflexions

56 paramètres

Δρmax = 0.80 e Å−3

Δρmin = −0.69 e Å−3

Collection des données: CAD-4 EXPRESS (Duisenberg, 1992 ▶; Macíček & Yordanov, 1992 ▶); affinement des paramètres de la maille: CAD-4 EXPRESS; réduction des données: XCAD4 (Harms & Wocadlo, 1995 ▶); programme(s) pour la solution de la structure: SHELXS97 (Sheldrick, 2008 ▶); programme(s) pour l’affinement de la structure: SHELXL97 (Sheldrick, 2008 ▶); graphisme moléculaire: DIAMOND (Brandenburg, 1998 ▶); logiciel utilisé pour préparer le matériel pour publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809002517/wm2218sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809002517/wm2218Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

NaMoO2(AsO4)	F(000) = 536
Mr = 289.85	Dx = 3.876 Mg m−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 25 reflections
a = 10.147 (2) Å	θ = 12–15°
b = 6.597 (2) Å	µ = 9.29 mm−1
c = 7.420 (2) Å	T = 298 K
V = 496.7 (2) Å3	Prism, yellow
Z = 4	0.26 × 0.16 × 0.10 mm

Enraf–Nonius CAD-4 diffractometer	539 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.027
graphite	θmax = 27.0°, θmin = 3.4°
ω/2θ scans	h = −1→12
Absorption correction: ψ scan (North et al., 1968)	k = −1→8
Tmin = 0.186, Tmax = 0.394	l = −9→9
1438 measured reflections	2 standard reflections every 120 min
589 independent reflections	intensity decay: 1.2%

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)] = 0.019	w = 1/[σ2(Fo2) + (0.0251P)2 + 0.2566P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.053	(Δ/σ)max = 0.001
S = 1.14	Δρmax = 0.80 e Å−3
589 reflections	Δρmin = −0.69 e Å−3
56 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 0.0099 (7)

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)
Mo1	0.32396 (4)	0.2500	0.44866 (5)	0.00991 (16)
As1	0.16109 (5)	0.2500	1.03646 (5)	0.00844 (16)
Na1	0.5123 (3)	0.0151 (6)	0.8833 (4)	0.0280 (7)	0.50
O1	0.6584 (3)	0.2500	1.0056 (5)	0.0213 (8)
O2	0.5243 (3)	0.2500	0.3365 (4)	0.0148 (7)
O3	0.3009 (3)	0.2500	0.1573 (4)	0.0120 (6)
O4	0.3898 (3)	0.2500	0.6593 (4)	0.0227 (8)
O5	0.1628 (2)	0.0465 (4)	0.8960 (3)	0.0172 (5)

	U11	U22	U33	U12	U13	U23
Mo1	0.0098 (2)	0.0112 (2)	0.0087 (2)	0.000	−0.00007 (14)	0.000
As1	0.0085 (2)	0.0086 (3)	0.0082 (2)	0.000	−0.00054 (16)	0.000
Na1	0.0261 (17)	0.0240 (18)	0.0339 (15)	−0.0048 (12)	−0.0057 (12)	−0.0035 (17)
O1	0.0145 (17)	0.031 (2)	0.0178 (15)	0.000	−0.0009 (13)	0.000
O2	0.0092 (14)	0.0224 (19)	0.0128 (15)	0.000	−0.0022 (13)	0.000
O3	0.0100 (14)	0.0131 (16)	0.0129 (14)	0.000	−0.0022 (12)	0.000
O4	0.0163 (17)	0.039 (2)	0.0124 (14)	0.000	−0.0019 (13)	0.000
O5	0.0231 (13)	0.0128 (11)	0.0158 (10)	−0.0016 (10)	−0.0028 (9)	−0.0042 (10)

Mo1—O4	1.700 (3)	As1—O5	1.700 (2)
Mo1—O1i	1.714 (3)	As1—O5v	1.700 (2)
Mo1—O5ii	1.999 (3)	Na1—O1	2.329 (4)
Mo1—O5iii	1.999 (3)	Na1—O2vi	2.420 (4)
Mo1—O3	2.174 (3)	Na1—O5vii	2.583 (4)
Mo1—O2	2.197 (3)	Na1—O4	2.590 (4)
As1—O2i	1.678 (3)	Na1—O1viii	2.595 (4)
As1—O3iv	1.678 (3)	Na1—O3vi	2.597 (4)
O4—Mo1—O1i	101.71 (16)	O1i—Mo1—O2	169.17 (14)
O4—Mo1—O5ii	98.82 (7)	O5ii—Mo1—O2	82.17 (7)
O1i—Mo1—O5ii	96.00 (7)	O5iii—Mo1—O2	82.17 (7)
O4—Mo1—O5iii	98.82 (7)	O3—Mo1—O2	73.93 (12)
O1i—Mo1—O5iii	96.00 (7)	O2i—As1—O3iv	113.51 (16)
O5ii—Mo1—O5iii	156.15 (12)	O2i—As1—O5	110.67 (10)
O4—Mo1—O3	163.05 (14)	O3iv—As1—O5	108.60 (10)
O1i—Mo1—O3	95.24 (14)	O2i—As1—O5v	110.67 (10)
O5ii—Mo1—O3	79.22 (6)	O3iv—As1—O5v	108.60 (10)
O5iii—Mo1—O3	79.22 (6)	O5—As1—O5v	104.37 (16)
O4—Mo1—O2	89.12 (14)

Table 1

Paramètres géométriques(Å)

Mo1—O4	1.700 (3)
Mo1—O1i	1.714 (3)
Mo1—O5ii	1.999 (3)
Mo1—O5iii	1.999 (3)
Mo1—O3	2.174 (3)
Mo1—O2	2.197 (3)
As1—O2i	1.678 (3)
As1—O3iv	1.678 (3)
As1—O5	1.700 (2)
As1—O5v	1.700 (2)
Na1—O1	2.329 (4)
Na1—O2vi	2.420 (4)
Na1—O5vii	2.583 (4)
Na1—O4	2.590 (4)
Na1—O1viii	2.595 (4)
Na1—O3vi	2.597 (4)

Codes de symétrie: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) .