Ag(MoO₂)(AsO₄)

Silver molybdyl arsenate has been synthesized by a solid-state reaction. The structure consists of AsO₄ tetrahedra and MoO₆ octahedra sharing corners to form a three-dimensional framwork containing channels running along [010], in which the Ag⁺ ions are located. Structural relationships between the different monoarsenates of the AMoO₂AsO₄ series (A = Ag, Li, Na, K and Rb) are discussed.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](As-O) = 0.005 Å
• R factor = 0.032
• wR factor = 0.097
• Data-to-parameter ratio = 13.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         Ag
PLAT301_ALERT_3_C Main Residue  Disorder .........................       9.00 Perc.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

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, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97.

Silver molybdyl arsenate

Crystal data

AgMoO2AsO4	F(000) = 680
Mr = 374.73	Dx = 5.201 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 25 reflections
a = 10.241 (1) Å	θ = 10–16°
b = 6.587 (1) Å	µ = 13.52 mm^−1
c = 7.095 (1) Å	T = 298 K
V = 478.61 (11) Å^3	Prism, yellow
Z = 4	0.20 × 0.15 × 0.10 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	724 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.035
Graphite monochromator	θmax = 30.0°, θmin = 3.5°
ω/2θ scans	h = −1→14
Absorption correction: ψ scan (North et al., 1968)	k = −9→3
Tmin = 0.108, Tmax = 0.264	l = −1→9
1278 measured reflections	2 standard reflections every 120 min
753 independent reflections	intensity decay: none

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)] = 0.032	w = 1/[σ^2(Fo^2) + (0.038P)^2 + 5.3764P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.097	(Δ/σ)max < 0.001
S = 1.24	Δρmax = 1.08 e Å^−3
753 reflections	Δρmin = −1.54 e Å^−3
56 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.075 (4)

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	Occ. (<1)
As	0.1596 (1)	0.2500	0.0332 (1)	0.0065 (2)
Mo	0.3312 (1)	0.2500	0.4490 (1)	0.0071 (2)
Ag	0.0059 (1)	0.5197 (3)	0.4486 (2)	0.0400 (4)	0.50
O1	0.3983 (5)	0.2500	0.6681 (7)	0.0178 (11)
O2	0.1681 (5)	0.2500	0.5013 (8)	0.0167 (11)
O3	0.3030 (5)	0.2500	0.1468 (7)	0.0106 (9)
O4	0.0282 (5)	0.2500	0.1747 (7)	0.0143 (10)
O5	0.3429 (4)	0.5444 (6)	0.3900 (5)	0.0135 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
As	0.0070 (4)	0.0064 (4)	0.0062 (4)	0.000	−0.0008 (2)	0.000
Mo	0.0077 (3)	0.0080 (3)	0.0056 (3)	0.000	0.0001 (2)	0.000
Ag	0.0331 (6)	0.0360 (8)	0.0510 (9)	0.0163 (5)	0.0041 (6)	−0.0034 (7)
O1	0.018 (2)	0.027 (3)	0.008 (2)	0.000	−0.001 (2)	0.000
O2	0.012 (2)	0.025 (3)	0.014 (2)	0.000	0.001 (2)	0.000
O3	0.008 (2)	0.016 (2)	0.007 (2)	0.000	−0.002 (2)	0.000
O4	0.009 (2)	0.025 (3)	0.009 (2)	0.000	0.002 (2)	0.000
O5	0.022 (2)	0.008 (2)	0.011 (2)	0.001 (1)	0.001 (1)	−0.003 (1)

Geometric parameters (Å, º)

As—O3	1.676 (5)	Mo—O4^iv	2.201 (5)
As—O4	1.678 (5)	Ag—O2^v	2.367 (4)
As—O5^i	1.694 (4)	Ag—O2	2.461 (4)
As—O5^ii	1.694 (4)	Ag—O4	2.640 (4)
Mo—O1	1.700 (5)	Ag—O1^ii	2.688 (4)
Mo—O2	1.710 (5)	Ag—O3^vi	2.816 (4)
Mo—O5^iii	1.987 (4)	Ag—O3^vii	2.846 (4)
Mo—O5	1.987 (4)	Ag—O5^vi	2.930 (4)
Mo—O3	2.163 (5)	Ag—O4^v	3.093 (4)
O3—As—O4	114.5 (3)	O5^iii—Mo—O5	154.7 (2)
O3—As—O5^i	107.6 (2)	O1—Mo—O3	163.8 (2)
O4—As—O5^i	110.3 (2)	O2—Mo—O3	94.9 (2)
O3—As—O5^ii	107.6 (2)	O5^iii—Mo—O3	78.4 (1)
O4—As—O5^ii	110.3 (2)	O5—Mo—O3	78.4 (1)
O5^i—As—O5^ii	106.2 (3)	O1—Mo—O4^iv	89.7 (2)
O1—Mo—O2	101.3 (3)	O2—Mo—O4^iv	169.0 (2)
O1—Mo—O5^iii	99.7 (1)	O5^iii—Mo—O4^iv	82.0 (1)
O2—Mo—O5^iii	96.0 (1)	O5—Mo—O4^iv	82.0 (1)
O1—Mo—O5	99.7 (1)	O3—Mo—O4^iv	74.2 (2)
O2—Mo—O5	96.0 (1)

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