Disodium tris­­(dioxidomolybdenum) bis­­(diarsenate)

The asymmetric unit of the title compound, Na₂(MoO₂)₃(As₂O₇)₂, is composed of two cyclic MoAs₂O₁₁ units and an MoO₆ corner-sharing octa­hedron. The anionic framework can be decomposed into two types of layers, viz. MoO₂As₂O₇ and Mo₂As₂O₁₄, which use mixed Mo—O—As and As—O—Mo bridges to achieve a new three-dimensional structure with two types of large channels in which the Na⁺ cations are located. Two O atoms are disordered and are located in two positions close to their initial positions with occupancy ratios of 0.612 (17):0.388 (17) and 0.703 (12):0.298 (12).

Related literature

For background to the search for new materials with open structures, see: Kierkegaard & Westerlund (1964); Lii et al. (1987); Guesdon et al. (1994); Masquelier et al. (1995). In these materials, the association of XO₄ (X = P, As) tetra­hedra and MO₆ (M = transition metal) octa­hedra forms covalent hybrid structures that delimit tunnels, see: Linnros (1970); Hammond & Barbier (1996). For details of the preparation, see: Zid & Jouini (1996a,b); Zid et al. (1997, 1998); Hajji et al. (2004); Hajji & Zid (2006); Ben Hlila et al. (2009). For related structures, see: Averbuch-Pouchot (1988, 1989); Zid et al. (2003); Lii & Wang (1989); Benhamada et al. (1992). For the properties of related compounds, see: Marzouki et al. (2010); Ouerfelli et al. (2007). For background to the bond-valence method, see: Brown & Altermatt (1985).

Experimental

Crystal data

• Na₂(MoO₂)₃(As₂O₇)₂

• M_r = 953.48

• Monoclinic, P 2₁ /c

• a = 14.571 (3) Å

• b = 12.580 (2) Å

• c = 9.258 (2) Å

• β = 94.51 (2)°

• V = 1691.9 (6) ų

• Z = 4

• Mo Kα radiation

• μ = 10.11 mm⁻¹

• T = 298 K

• 0.26 × 0.18 × 0.14 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: ψ scan (North et al., 1968) T_min = 0.133, T_max = 0.246

• 4271 measured reflections

• 3676 independent reflections

• 3128 reflections with I > 2σ(I)

• R_int = 0.022

• 2 standard reflections every 120 min intensity decay: 1.1%

Refinement

• R[F² > 2σ(F²)] = 0.025

• wR(F²) = 0.060

• S = 1.06

• 3676 reflections

• 273 parameters

• 2 restraints

• Δρ_max = 0.98 e Å⁻³

• Δρ_min = −0.75 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, 1998); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supporting information

S1. Comment

The search for new materials with open structure has motivated many works (Kierkegaard & Westerlund, 1964; Lii et al., 1987; Guesdon et al., 1994; Masquelier et al., 1995). In these materials, the association of XO₄ (X=P, As) tetrahedra and MO₆ (M= transition metal) octahedra forms covalent hybrid structures that delimit tunnels (Linnros, 1970; Hammond & Barbier, 1996) or interlayers favorable to the migration of cations. For instance, the junction between these polyhedra can develop new materials that could have properties associated with the ion mobility of metal cations. This area is far from being fully explored and represents a field of considerable activity including several disciplines. In this context the A—Mo—As—O (A = monovalent cation) systems were explored and several interesting phases: K₂MoO₂As₂O₇ (Zid & Jouini, 1996a), Rb₂MoO₂As₂O₇ (Zid et al., 1998) and K₂MoO₂(MoO₂As₂O₇)₂ (Zid & Jouini, 1996b) were characterized. Herein, we describe the synthesis of a new material of monoclinic symmetry by solid state reaction. The method of preparation, structure determination by X-ray diffraction on single-crystal and physical properties are presented. The new Na₂(MoO₂)₃(As₂O₇)₂ phase presents a three-dimensional framework. The asymmetric unit is built from two cyclic MoAs₂O₁₁ units and MoO₆ corner-sharing octahedron (Fig. 1). The anionic framework of Na₂(MoO₂)₃(As₂O₇)₂ can be decomposed into two layers: the first found in the material K₂MoO₂(MoO₂As₂O₇)₂ (Zid & Jouini, 1996b), and the second Mo₂As₂O₁₄ layer which is new. Layers (Mo2O₂As₂O₇) are constructed from conventional Mo2As₂O₁₁ units in which each diarsenate group shares two oxygen atoms with the Mo2O₆ octahedron. Units Mo2As₂O₁₁ are pairs connected to form double [Mo2₂As₄O₂₀] units. The junction between the latter sharing corners with polyhedra of different nature, leads to the (Mo2O₂As₂O₇) layer (Fig. 2) in which each Mo2O₆ octahedron shares four of its corners with only three As₂O₇ groups. The other two free remaining corners form the Mo2O₂ molybdyl group directed to large elongated parallel channels arranged to the [100] direction resulting from the combination of four double [Mo2₂As₄O₂₀] units. The layers of the second type are built from new units of formula Mo₂As₂O₁₆ (Fig. 3). These are due to the association between a conventional Mo1As₂O₁₁ unit and Mo3O₆ octahedron by corner-sharing. In addition, each Mo₂As₂O₁₆ unit binds to its centrosymmetric according to [001] direction forming double Mo₄As₄O₃₀ units. The latter are connected by corner-sharing and form new layers of Mo₂As₂O₁₄ type, which are organized in a wavy arrangement according to the plans (010) (Fig. 4). Within these layers there are two types of channels, hexagonal or square sections, arranged in the [010] direction. The anionic framework is constructed by the two types of layers previously described (Mo2O₂As₂O₇)) (Fig. 2) and Mo₂As₂O₁₄ (Fig. 4) using mixte Mo—O—As and As—O—Mo bridges leading to a new three-dimensional framework with large channels of two types where the Na⁺ cations are located (Fig. 5). The average Mo—O, As—O and Na—O distances in the structure are consistent with those found in the literature (Zid et al., 1997; Hajji et al., 2004; Hajji & Zid, 2006; Ben Hlila et al., 2009). In addition, the calculation of the various valence bonds (BVS) using empirical formula of Brown (Brown & Altermatt, 1985) confirms the expected values of ion charges: Mo1(5,967), Mo2(6,017), Mo3(6,021), As1(4,966), As2(4,990), As3(5,016), As4(4,981), Na1(0,606) and Na2(0,902). The phase studied is new but the comparaison of the structure of Na₂(MoO₂)₃(As₂O₇)₂ with those found in the literature for related MX₂O₁₁ (X=P, As) units reveals some structural affiliation. In the diphosphates of formula A₂MoO₂P₂O₇ (A=Cs (Averbuch-Pouchot, 1988); A= NH₄ (Averbuch-Pouchot, 1989); A=K (Zid et al., 2003)), MoP₂O₁₁ units are connected by cornrer-sharing octahedra and tetrahedra to form ribbons leading to a one-dimensional framework. The combination of ribbons of type MO₂X₂O₇ (M= transition metal, X= P, As) by M—O—X mixed bridges leads to layered structures similar to those encountered in diphosphates of the formula A₂VOP₂O₇ (A=Rb (Lii & Wang, 1989); A=Na (Benhamada et al., 1992)). The combination of such layers can lead to different three-dimensional frameworks. The structure of K₂MoO₂(MoO₂As₂O₇)₂ (Zid & Jouini, 1996b) was obtained by insertion of the MoO₂ group between MoO₂As₂O₇ layers, but in our case the two types of layers in Na₂(MoO₂)₃(As₂O₇)₂ are connected directly by mixed Mo—O—As and As—O—Mo bridges. In order to use the structural data obtained which are in favor of a good ion mobility and related to physicochemical properties and in particular ionic conduction, measurements of resistance as a function of temperature were carried out using an impedance analyzer of type HP4192A of a pure sample compacted in pellet and having a geometric factor of (e/s=0,017 cm^-1). The values of the conductivities obtained by rising temperatures correlate well with the Arrhenius law: Ln(σT) = f(10⁴/T). These results show that this material has an activation energy of 0,79 eV and a conductivity of 4,294 10^-5 S.cm^-1 at 793 K indicating that the material can be classified as a mild ionic conductor. These results are comparable to those found in the literature for compounds with cobalt (Marzouki et al., 2010) and iron (Ouerfelli et al., 2007).

Related literature

For background to the search for new materials with open structures, see: Kierkegaard & Westerlund (1964); Lii et al. (1987); Guesdon et al. (1994); Masquelier et al. (1995). In these materials, the association of XO₄ (X = P, As) tetrahedra and MO₆ (M = transition metal) octahedra forms covalent hybrid structures that delimit tunnels, see: Linnros (1970); Hammond & Barbier (1996). For details of the preparation see: Zid & Jouini (1996a,b); Zid et al. (1997, 1998); Hajji et al. (2004); Hajji & Zid (2006); Ben Hlila et al. (2009). For related structures, see: Averbuch-Pouchot (1988, 1989); Zid et al. (2003); Lii & Wang (1989); Benhamada et al. (1992). For the properties of related compounds, see: Marzouki et al. (2010); Ouerfelli et al. (2007). For bond valences, see: Brown & Altermatt (1985).

S2. Experimental

The crystals of the Na₂(MoO₂)₃(As₂O₇)₂ phase were obtained from the reagents: (NH₄)₂Mo₄O₁₃ (Fluka, 69858), NH₄H₂AsO₄ (prepared in the laboratory, ASTM 01–775) and Na₂CO₃ (Prolabo, 27778) taken in Na: Mo: As molar ratio of 2: 3: 4. The finely ground mixture was preheated in air at 623 K to remove volatile compounds. It was then heated, in steps of 100 degrees followed by grinding to a temperature close to the melting point 828 K. The mixture was then left at this temperature for one week to promote germination and growth of crystals. The final residue was subjected to cooling first a slow (5°/half-day at 778 K) and a second faster (50°/h) to room temperature. Yellow crystals of sufficient size for the measurements of intensities, were separated from refluxing water. A qualitative analysis of a selected crystal by scanning electron microscopy (S.E.M) of the type FEI Quanta 200 under polarizing microscope, confirmed the presence of different chemical elements expected: As, Mo, Na and oxygen.

S3. Refinement

In the final refinement, examination of the Fourier-Difference reveals the presence of two peaks which are close to the oxygen atoms O19 and O20. In addition, the thermal motion of these atoms is relatively high, so each oxygen atom is distribute between two positions with variable occupancy ratios satisfying the condition of electrical neutrality of the material. For this, the use of two conditions SUMP and EADP allowed by the SHELX program is necessary. The ellipsoids of the atoms considered are better defined.

Computing details

Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); 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, 1998); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. : The asymmetric unit of Na2(MoO2)3(As2O7)2. Displacement ellipsoids are drawn at the 50% probability level. symmetry codes:(i) -x + 1, y + 1/2, -z + 1/2; (ii) -x + 1, y - 1/2, -z + 1/2; (iii) x, -y + 1/2, z + 1/2; (iv) -x + 1, y + 1/2, -z + 3/2; (v) x + 1, y, z; (vi) x + 1, y, z - 1; (vii) -x + 1, -y + 1, -z + 1; (viii) -x + 1, y - 1/2, -z + 3/2.
	Fig. 2. : Representation of the (Mo2O2As2O7) layer along the a axis.
	Fig. 3. : Representation of Mo2As2O16 unit.
	Fig. 4. : Projection of Mo2As2O14 layer along the c axis.
	Fig. 5. : Projection of structure according to c axis, showing the channel where Na^+ cations are located.

Disodium tris(dioxidomolybdenum) bis(diarsenate)

Crystal data

Na2(MoO2)3(As2O7)2	F(000) = 1760
Mr = 953.48	Dx = 3.743 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 14.571 (3) Å	θ = 10–15°
b = 12.580 (2) Å	µ = 10.11 mm^−1
c = 9.258 (2) Å	T = 298 K
β = 94.51 (2)°	Prism, yellow
V = 1691.9 (6) Å^3	0.26 × 0.18 × 0.14 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	3128 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.022
Graphite monochromator	θmax = 27.0°, θmin = 2.1°
ω/2θ scans	h = −18→18
Absorption correction: ψ scan (North et al., 1968)	k = −1→16
Tmin = 0.133, Tmax = 0.246	l = −11→1
4271 measured reflections	2 standard reflections every 120 min
3676 independent reflections	intensity decay: 1.1%

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)] = 0.025	w = 1/[σ^2(Fo^2) + (0.0188P)^2 + 7.737P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.060	(Δ/σ)max = 0.001
S = 1.06	Δρmax = 0.98 e Å^−3
3676 reflections	Δρmin = −0.75 e Å^−3
273 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
2 restraints	Extinction coefficient: 0.00106 (6)

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)
Mo1	0.31869 (3)	0.06243 (4)	0.05295 (4)	0.01284 (10)
Mo2	0.02062 (3)	0.37400 (3)	0.26296 (5)	0.01470 (11)
Mo3	0.70516 (3)	0.12821 (3)	0.42003 (4)	0.00864 (10)
As1	0.53859 (3)	0.00042 (4)	0.20483 (5)	0.00852 (11)
As2	0.60470 (3)	0.33825 (4)	0.24714 (5)	0.00885 (11)
As3	0.00777 (3)	0.62745 (4)	0.12380 (6)	0.01163 (11)
As4	0.81642 (3)	0.53068 (4)	0.18604 (5)	0.00924 (11)
Na1	0.4171 (2)	0.1428 (2)	0.4537 (3)	0.0381 (7)
Na2	0.13444 (18)	0.8679 (2)	0.9496 (3)	0.0343 (6)
O1	0.6093 (2)	0.0020 (3)	0.3549 (4)	0.0129 (7)
O2	0.5933 (2)	0.0231 (3)	0.0556 (4)	0.0146 (7)
O3	0.7475 (2)	0.6100 (3)	0.2769 (4)	0.0150 (7)
O4	0.1230 (3)	0.3287 (3)	0.2208 (5)	0.0291 (10)
O5	0.5893 (2)	0.3594 (3)	0.0702 (4)	0.0163 (7)
O6	0.7499 (3)	0.4947 (3)	0.0395 (4)	0.0189 (8)
O7	0.3449 (3)	0.1862 (3)	0.9950 (4)	0.0276 (9)
O8	0.7566 (3)	0.2271 (3)	0.5219 (4)	0.0225 (8)
O9	0.6874 (2)	0.4098 (3)	0.3346 (4)	0.0136 (7)
O10	0.8787 (2)	0.4405 (3)	0.2789 (4)	0.0161 (7)
O11	0.4431 (2)	0.0715 (3)	0.2150 (4)	0.0125 (7)
O12	0.0325 (3)	0.3820 (4)	0.4454 (5)	0.0425 (12)
O13	0.2237 (3)	0.0292 (4)	0.9471 (4)	0.0259 (9)
O14	0.8884 (2)	0.6242 (3)	0.1131 (4)	0.0149 (7)
O15	0.7762 (2)	0.1145 (3)	0.2859 (4)	0.0222 (9)
O16	0.5032 (2)	0.8672 (3)	0.1910 (4)	0.0123 (7)
O17	0.6118 (2)	0.2098 (3)	0.2942 (4)	0.0147 (7)
O18	0.0423 (3)	0.7296 (3)	0.2295 (5)	0.0366 (12)
O19	0.0424 (7)	0.6173 (10)	0.9610 (11)	0.0191 (19)	0.612 (17)
O191	0.0395 (12)	0.6633 (14)	0.9569 (19)	0.0191 (19)	0.388 (17)
O20	0.0489 (4)	0.5281 (5)	0.2364 (9)	0.0181 (15)	0.703 (12)
O201	0.0481 (10)	0.5117 (13)	0.164 (2)	0.0181 (15)	0.298 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mo1	0.00827 (19)	0.0211 (2)	0.0093 (2)	0.00355 (16)	0.00231 (15)	0.00338 (16)
Mo2	0.0095 (2)	0.0139 (2)	0.0205 (2)	−0.00034 (16)	0.00001 (17)	0.00670 (17)
Mo3	0.00620 (19)	0.0103 (2)	0.0094 (2)	0.00053 (15)	0.00019 (14)	0.00045 (15)
As1	0.0061 (2)	0.0123 (2)	0.0073 (2)	−0.00051 (17)	0.00123 (17)	−0.00062 (17)
As2	0.0072 (2)	0.0101 (2)	0.0095 (2)	0.00085 (17)	0.00259 (17)	0.00266 (18)
As3	0.0083 (2)	0.0091 (2)	0.0182 (3)	−0.00207 (18)	0.00470 (19)	−0.00203 (19)
As4	0.0057 (2)	0.0116 (2)	0.0105 (2)	−0.00142 (17)	0.00102 (17)	−0.00197 (18)
Na1	0.0537 (17)	0.0409 (15)	0.0194 (12)	0.0219 (13)	−0.0001 (11)	−0.0080 (11)
Na2	0.0316 (14)	0.0373 (15)	0.0341 (14)	0.0110 (11)	0.0024 (11)	0.0004 (11)
O1	0.0126 (17)	0.0139 (17)	0.0115 (17)	−0.0014 (14)	−0.0039 (13)	−0.0012 (13)
O2	0.0116 (17)	0.0240 (19)	0.0091 (17)	0.0022 (14)	0.0064 (13)	0.0021 (14)
O3	0.0155 (17)	0.0130 (17)	0.0179 (18)	−0.0009 (14)	0.0091 (14)	−0.0030 (14)
O4	0.017 (2)	0.023 (2)	0.048 (3)	0.0010 (17)	0.0076 (19)	0.0048 (19)
O5	0.0149 (18)	0.0234 (19)	0.0107 (17)	−0.0006 (15)	0.0011 (14)	0.0043 (14)
O6	0.023 (2)	0.0188 (19)	0.0137 (18)	−0.0089 (15)	−0.0053 (15)	−0.0032 (15)
O7	0.028 (2)	0.027 (2)	0.029 (2)	0.0067 (18)	0.0126 (18)	0.0129 (18)
O8	0.0198 (19)	0.021 (2)	0.025 (2)	−0.0005 (15)	−0.0092 (16)	−0.0054 (16)
O9	0.0109 (16)	0.0136 (17)	0.0163 (18)	0.0005 (13)	0.0003 (14)	0.0004 (14)
O10	0.0095 (16)	0.0187 (18)	0.0203 (19)	0.0036 (14)	0.0024 (14)	0.0041 (15)
O11	0.0084 (16)	0.0156 (18)	0.0135 (17)	0.0012 (13)	0.0012 (13)	−0.0039 (14)
O12	0.029 (2)	0.068 (4)	0.029 (3)	0.002 (2)	−0.001 (2)	0.003 (2)
O13	0.0128 (18)	0.047 (3)	0.017 (2)	0.0070 (18)	−0.0025 (15)	−0.0025 (18)
O14	0.0055 (16)	0.0152 (18)	0.025 (2)	−0.0020 (13)	0.0052 (14)	0.0046 (15)
O15	0.0131 (18)	0.032 (2)	0.023 (2)	0.0060 (16)	0.0096 (15)	0.0064 (17)
O16	0.0087 (16)	0.0129 (17)	0.0159 (17)	−0.0016 (13)	0.0049 (13)	−0.0016 (13)
O17	0.0126 (17)	0.0088 (16)	0.0218 (19)	0.0015 (13)	−0.0041 (14)	0.0032 (14)
O18	0.015 (2)	0.024 (2)	0.069 (3)	0.0017 (17)	−0.004 (2)	−0.030 (2)
O19	0.012 (2)	0.030 (6)	0.017 (2)	0.006 (5)	0.0075 (17)	0.005 (5)
O191	0.012 (2)	0.030 (6)	0.017 (2)	0.006 (5)	0.0075 (17)	0.005 (5)
O20	0.013 (2)	0.019 (3)	0.021 (4)	−0.0069 (19)	−0.009 (3)	0.009 (3)
O201	0.013 (2)	0.019 (3)	0.021 (4)	−0.0069 (19)	−0.009 (3)	0.009 (3)

Geometric parameters (Å, º)

Mo1—O13^i	1.684 (4)	As2—O9	1.663 (3)
Mo1—O7^i	1.700 (4)	As2—O17	1.675 (3)
Mo1—O3^ii	2.002 (3)	As2—O16^ii	1.753 (3)
Mo1—O2^iii	2.003 (3)	As3—O19^i	1.631 (10)
Mo1—O9^ii	2.189 (3)	As3—O18	1.669 (4)
Mo1—O11	2.264 (3)	As3—O20	1.706 (6)
Mo2—O4	1.672 (4)	As3—O14^vi	1.735 (3)
Mo2—O12	1.688 (5)	As4—O10	1.651 (3)
Mo2—O20	2.002 (6)	As4—O6	1.666 (3)
Mo2—O18^iv	2.038 (4)	As4—O3	1.686 (3)
Mo2—O19^v	2.204 (10)	As4—O14	1.747 (3)
Mo2—O10^vi	2.246 (3)	Na1—O7^ix	2.438 (5)
Mo3—O15	1.686 (4)	Na1—O11	2.442 (4)
Mo3—O8	1.699 (4)	Na1—O1^x	2.592 (4)
Mo3—O6^vii	1.982 (3)	Na1—O5^vii	2.652 (4)
Mo3—O17	2.003 (3)	Na2—O8^xi	2.379 (5)
Mo3—O1	2.168 (3)	Na2—O13^xii	2.412 (5)
Mo3—O5^vii	2.275 (4)	Na2—O20^xiii	2.603 (8)
As1—O11	1.663 (3)	Na2—O15^xiv	2.636 (5)
As1—O1	1.664 (3)	Na2—O18^xiii	2.651 (6)
As1—O2	1.673 (3)	Na2—O10^xi	2.695 (4)
As1—O16^viii	1.755 (3)	Na2—O12^xv	2.695 (5)
As2—O5	1.657 (3)
O13^i—Mo1—O7^i	103.8 (2)	O11—As1—O16^viii	105.99 (16)
O13^i—Mo1—O3^ii	96.13 (17)	O1—As1—O16^viii	103.40 (16)
O7^i—Mo1—O3^ii	96.25 (17)	O2—As1—O16^viii	105.00 (17)
O13^i—Mo1—O2^iii	95.99 (17)	O5—As2—O9	115.52 (17)
O7^i—Mo1—O2^iii	99.49 (17)	O5—As2—O17	114.38 (18)
O3^ii—Mo1—O2^iii	157.22 (14)	O9—As2—O17	111.62 (17)
O13^i—Mo1—O9^ii	89.84 (17)	O5—As2—O16^ii	103.55 (17)
O7^i—Mo1—O9^ii	166.34 (17)	O9—As2—O16^ii	111.25 (16)
O3^ii—Mo1—O9^ii	81.23 (13)	O17—As2—O16^ii	98.86 (16)
O2^iii—Mo1—O9^ii	79.59 (13)	O19^i—As3—O18	120.1 (5)
O13^i—Mo1—O11	167.66 (18)	O19^i—As3—O20	112.8 (5)
O7^i—Mo1—O11	88.54 (17)	O18—As3—O20	97.5 (3)
O3^ii—Mo1—O11	82.75 (13)	O19^i—As3—O14^vi	109.1 (4)
O2^iii—Mo1—O11	81.30 (13)	O18—As3—O14^vi	107.80 (18)
O9^ii—Mo1—O11	77.84 (12)	O20—As3—O14^vi	108.7 (2)
O4—Mo2—O12	103.3 (2)	O10—As4—O6	119.85 (18)
O4—Mo2—O20	96.0 (2)	O10—As4—O3	118.10 (18)
O12—Mo2—O20	93.4 (3)	O6—As4—O3	103.65 (18)
O4—Mo2—O18^iv	96.68 (19)	O10—As4—O14	110.01 (17)
O12—Mo2—O18^iv	91.7 (2)	O6—As4—O14	101.34 (18)
O20—Mo2—O18^iv	164.8 (2)	O3—As4—O14	101.14 (16)
O4—Mo2—O19^v	96.4 (3)	O7^ix—Na1—O11	124.45 (17)
O12—Mo2—O19^v	160.3 (3)	O7^ix—Na1—O1^x	115.09 (16)
O20—Mo2—O19^v	84.9 (4)	O11—Na1—O1^x	113.72 (15)
O18^iv—Mo2—O19^v	85.5 (3)	O7^ix—Na1—O5^vii	110.59 (16)
O4—Mo2—O10^vi	170.19 (18)	O11—Na1—O5^vii	98.91 (14)
O12—Mo2—O10^vi	86.26 (19)	O1^x—Na1—O5^vii	84.34 (13)
O20—Mo2—O10^vi	81.20 (19)	O8^xi—Na2—O13^xii	105.79 (16)
O18^iv—Mo2—O10^vi	84.89 (15)	O8^xi—Na2—O20^xiii	137.2 (2)
O19^v—Mo2—O10^vi	74.1 (3)	O13^xii—Na2—O20^xiii	78.22 (17)
O15—Mo3—O8	102.3 (2)	O8^xi—Na2—O15^xiv	77.62 (15)
O15—Mo3—O6^vii	97.89 (17)	O13^xii—Na2—O15^xiv	67.62 (15)
O8—Mo3—O6^vii	98.61 (17)	O20^xiii—Na2—O15^xiv	64.43 (18)
O15—Mo3—O17	93.01 (17)	O8^xi—Na2—O18^xiii	91.96 (15)
O8—Mo3—O17	101.38 (16)	O13^xii—Na2—O18^xiii	128.51 (16)
O6^vii—Mo3—O17	154.59 (15)	O20^xiii—Na2—O18^xiii	57.74 (16)
O15—Mo3—O1	98.02 (17)	O15^xiv—Na2—O18^xiii	69.91 (14)
O8—Mo3—O1	159.50 (17)	O8^xi—Na2—O10^xi	104.17 (15)
O6^vii—Mo3—O1	76.15 (14)	O13^xii—Na2—O10^xi	78.55 (14)
O17—Mo3—O1	79.65 (13)	O20^xiii—Na2—O10^xi	118.17 (18)
O15—Mo3—O5^vii	169.94 (16)	O15^xiv—Na2—O10^xi	144.98 (16)
O8—Mo3—O5^vii	85.81 (16)	O18^xiii—Na2—O10^xi	143.58 (16)
O6^vii—Mo3—O5^vii	86.56 (15)	O8^xi—Na2—O12^xv	128.48 (19)
O17—Mo3—O5^vii	79.47 (14)	O13^xii—Na2—O12^xv	116.79 (18)
O1—Mo3—O5^vii	74.19 (13)	O20^xiii—Na2—O12^xv	81.29 (19)
O11—As1—O1	114.32 (17)	O15^xiv—Na2—O12^xv	144.23 (17)
O11—As1—O2	114.23 (17)	O18^xiii—Na2—O12^xv	83.71 (16)
O1—As1—O2	112.56 (17)	O10^xi—Na2—O12^xv	60.61 (13)

Symmetry codes: (i) x, y, z−1; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+1, −y, −z; (iv) −x, y−1/2, −z+1/2; (v) −x, −y+1, −z+1; (vi) x−1, y, z; (vii) x, −y+1/2, z+1/2; (viii) x, y−1, z; (ix) x, −y+1/2, z−1/2; (x) −x+1, −y, −z+1; (xi) −x+1, y+1/2, −z+3/2; (xii) x, y+1, z; (xiii) x, −y+3/2, z+1/2; (xiv) −x+1, −y+1, −z+1; (xv) −x, y+1/2, −z+3/2.