Penta­potassium μ-arsenato-bis­(hy­droxy­tetra­molybdate) dihydrate

Yu, H.-H.; Kong, L.; Cui, J.-W.; Wang, H.-T.

doi:10.1107/S1600536810054176

inorganic compounds

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ISSN: 2056-9890

Volume 67| Part 2| February 2011| Page i15

doi:10.1107/S1600536810054176

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Pentapotassium μ-arsenato-bis(hydroxytetramolybdate) dihydrate

Hai-Hui Yu,^a Li Kong,^b ^* Ji-Wen Cui ^c and Hai-Tao Wang ^d

^aCollege of Chemical Engineering, Northeast Dianli University, Jilin 132012, People's Republic of China, ^bJilin Institute of Chemical Technology, Jilin 132012, People's Republic of China, ^cCollege of Chemistry and Pharmacy, Jiamusi University, Jiamusi 154000, People's Republic of China, and ^dChemical Engineering Department, Huizhou University, Huizhou 516001, People's Republic of China
^*Correspondence e-mail: kongli99@yahoo.cn

(Received 19 October 2010; accepted 25 December 2010; online 15 January 2011)

The title arsenatomolybdate, K₅[Mo₈O₂₄(OH)₂(AsO₄)]·2H₂O, which was obtained hydrothermally, features an [AsMo₈O₂₈(OH)₂]⁵⁻ anion, which is formed by two Mo₄O₁₄(OH) units that are linked by As in a sandwich-like fashion. The overall symmetry of the anion is m2m. The {Mo₄O₁₄(OH)} core is composed of two pairs of confacial bioctahedral {Mo₂O₉} units with two μ₄-O atoms which have been characterized as hydroxyl groups. The anions are further interconnected by potassium cations, forming a three-dimensional network structure with the uncoordinated water molecules occupying the channels. The structure is further stabilized by O—H⋯O hydrogen bonding.

Related literature

For isotypic K_5-x(NH₄)_xP[Mo₄O₁₄(OH)]₂·2H₂O (x = 2.43), see: Chen et al. (2009 ). For a general overview of polyoxometalates, see: Pope (1983 ). For the Mo/As/O system, see: Sun et al. (2007 ); He & Wang (1999 ). For bond-valence-sum calculatios, see: Brown (1981 ); Hsu & Wang (1997 ).

Experimental

Crystal data

K₅[Mo₈O₂₄(OH)₂(AsO₄)]·2H₂O
M_r = 1553.95
Orthorhombic, C m c m
a = 8.3024 (12) Å
b = 23.008 (3) Å
c = 15.279 (2) Å
V = 2918.6 (7) Å³
Z = 4
Mo Kα radiation
μ = 5.28 mm⁻¹
T = 293 K
0.20 × 0.18 × 0.16 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ) T_min = 0.418, T_max = 0.486
12346 measured reflections
1606 independent reflections
1216 reflections with I > 2σ(I)
R_int = 0.048

Refinement

R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.098
S = 1.07
1606 reflections
133 parameters
Only H-atom coordinates refined
Δρ_max = 1.99 e Å⁻³
Δρ_min = −0.72 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1⋯O12ⁱ	0.82 (9)	2.06 (9)	2.831 (11)	157 (9)
O11—H4⋯O1W	0.87 (11)	1.81 (11)	2.684 (13)	180 (1)
Symmetry code: (i) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: RAPID-AUTO (Rigaku, 1998 ); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2007 ); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810054176/fi2098sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810054176/fi2098Isup2.hkl

checkCIF report

Comment top

Polyoxometalates(POMs) are metal-oxygen anionic clusters, which act as multidentate inorganic ligands. They can bind most transition metals, rare earth metals and alkali metals, leading to a family of compounds with a variety of structures (Pope, 1983). Performing as an important part in this field, a number of compounds from the A/Mo/P/O system have been synthesized and structurally characterized, where A is an organic or inorganic cation. In contrast to the rich structural chemistry of molybdenum phosphates, the Mo/As/O system remains relatively undeveloped (Sun et al., 2007; He & Wang, 1999). Here, we have hydrothermally synthesized the title compound, K₅Mo₈O₂₄(OH)₂AsO₄.2H₂O, which is isostructural with K_5-x(NH₄)_xP[Mo₄O₁₄(OH)]₂.2 H₂O where x=2.43 (Chen et al. (2009).

The structure of the title compound consists of [AsMo₈O₂₈(OH)₂]^5-cluster anions, K⁺ cations, and water molecules (Fig. 1). The anion is formed by two crystallographically independent {Mo₄O₁₄(OH)}cores, linked by an arsenic(V) atom in a sandwich-like fashion. The anion possesses m2m symmetry in that all four molybdenum atoms in the {Mo₄O₁₄(OH)}core are coplanar, and one oxygen atom in each core is characterized as hydroxyl (O4 and O11) which is indicated by literature and bond valence sum calculation value (Hsu & Wang 1997, Brown et al., 1981). The [AsMo₈O₃₀H₂]^5-cluster anions are bridged together by K⁺ cations into one-dimensional strings firstly. The anion-cation interactions are further extended into a three-dimensional architecture by other two K⁺ cations with each linking four cluster anions and one water molecule.

Related literature top

For isotypic K_5-_x(NH₄)_xP[Mo₄O₁₄(OH)]₂.2H₂O (x = 2.43), see: Chen et al. (2009). For a general overview of polyoxometalates, see: Pope (1983). For the Mo/As/O system, see: Sun et al. (2007); He & Wang (1999). For bond-valence-sum calculatios, see: Brown (1981); Hsu & Wang (1997).

Experimental top

The title compound was synthesized by hydrothermal reaction of Fe(NO₃)₃.9 H₂O(2.5 mmol),As₂O₃(2.5 mmol), MoO₃.2H₂O (3.0 mmol),KOH (5.0 mmol) and H₂O(18 ml) were stirred for 120 min. The pH of the mixture was adjusted to 6.5 with 1M nitric acid. The resultant mixture was sealed in a 25 ml Teflon-lined autoclave andheated at 180 ^oC for 8 d. The autoclave was then cooled to room temperature. The crystalline product was filtered, washed with distilled water and dried at ambient temperature to give black block solids.

Computing details top

Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO (Rigaku, 1998); data reduction: RAPID-AUTO (Rigaku, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2007); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. ORTEP drawing of the title compound withthermal ellipsoids at 50% probability.
	Fig. 2. A polyhedral representationof the three-dimensional network structure of the title compound. All of the water molecular is omitted forclarity. [symmetry codes:(i) x, y,z; (ii) -x, -y, 1/2 + z; (iii) x, -y, -z; (iv) -x, y, 1/2 - z; (v) -x, -y, -z; (vi) x, y, 1/2 + z; (vii) -x, y, z; (viii) x, -y, 1/2 + z.]

Pentapotassium µ-arsenato-bis(hydroxytetramolybdate) dihydrate top

Crystal data top

K₅[Mo₈O₂₄(OH)₂(AsO₄)]·2H₂O	F(000) = 2904
M_r = 1553.95	D_x = 3.541 Mg m⁻³
Orthorhombic, Cmcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2c 2	Cell parameters from 3063 reflections
a = 8.3024 (12) Å	θ = 2.6–26.0°
b = 23.008 (3) Å	µ = 5.28 mm⁻¹
c = 15.279 (2) Å	T = 293 K
V = 2918.6 (7) Å³	Block, black
Z = 4	0.20 × 0.18 × 0.16 mm

Data collection top

Rigaku R-AXIS RAPID diffractometer	1606 independent reflections
Radiation source: fine-focus sealed tube	1216 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.048
Detector resolution: 10 pixels mm^-1	θ_max = 26.0°, θ_min = 2.2°
ω scans	h = −10→10
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −28→28
T_min = 0.418, T_max = 0.486	l = −18→18
12346 measured reflections

Refinement top

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.098	Only H-atom coordinates refined
S = 1.07	w = 1/[σ²(F_o²) + (0.055P)²] where P = (F_o² + 2F_c²)/3
1606 reflections	(Δ/σ)_max < 0.001
133 parameters	Δρ_max = 1.99 e Å⁻³
0 restraints	Δρ_min = −0.72 e Å⁻³

Crystal data top

K₅[Mo₈O₂₄(OH)₂(AsO₄)]·2H₂O	V = 2918.6 (7) Å³
M_r = 1553.95	Z = 4
Orthorhombic, Cmcm	Mo Kα radiation
a = 8.3024 (12) Å	µ = 5.28 mm⁻¹
b = 23.008 (3) Å	T = 293 K
c = 15.279 (2) Å	0.20 × 0.18 × 0.16 mm

Data collection top

Rigaku R-AXIS RAPID diffractometer	1606 independent reflections
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	1216 reflections with I > 2σ(I)
T_min = 0.418, T_max = 0.486	R_int = 0.048
12346 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	0 restraints
wR(F²) = 0.098	Only H-atom coordinates refined
S = 1.07	Δρ_max = 1.99 e Å⁻³
1606 reflections	Δρ_min = −0.72 e Å⁻³
133 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
O2W	0.5000	0.3660 (4)	0.7500	0.046 (3)
H2W	0.4128	0.3599	0.7224	0.069*	0.50
Mo1	0.30043 (6)	0.49010 (2)	0.35477 (3)	0.01904 (18)
Mo2	0.30698 (6)	0.26333 (2)	0.35911 (3)	0.02029 (18)
As1	0.5000	0.37665 (4)	0.2500	0.0140 (3)
K1	0.0000	0.38267 (14)	0.2500	0.0504 (10)
K2	0.5000	0.12103 (8)	0.46558 (14)	0.0300 (5)
K3	0.5000	0.36453 (9)	0.52457 (14)	0.0341 (5)
O12	0.1808 (7)	0.5103 (3)	0.2500	0.0332 (16)
O11	0.5000	0.2312 (3)	0.2500	0.0198 (18)
O10	0.1715 (6)	0.4466 (2)	0.4095 (3)	0.0379 (12)
O9	0.5000	0.4605 (3)	0.3962 (4)	0.0328 (15)
O8	0.2890 (6)	0.55608 (19)	0.4041 (3)	0.0404 (13)
O7	0.2196 (7)	0.1971 (2)	0.3681 (3)	0.0516 (15)
O6	0.5000	0.2443 (3)	0.4234 (4)	0.0341 (16)
O5	0.2029 (6)	0.30763 (19)	0.4280 (3)	0.0382 (12)
O4	0.5000	0.5206 (3)	0.2500	0.0189 (17)
O3	0.3350 (7)	0.4194 (2)	0.2500	0.0268 (14)
O2	0.5000	0.3333 (2)	0.3397 (4)	0.0288 (15)
O1	0.2301 (8)	0.2928 (3)	0.2500	0.0338 (15)
O1W	0.5000	0.1146 (4)	0.2500	0.067 (5)
H1	0.426 (11)	0.091 (4)	0.2500	0.04 (3)*
H4	0.5000	0.193 (5)	0.2500	0.02 (3)*
H3	0.5000	0.562 (5)	0.2500	0.02 (3)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O2W	0.046 (7)	0.017 (5)	0.076 (8)	0.000	0.000	0.000
Mo1	0.0219 (3)	0.0168 (3)	0.0184 (3)	0.0015 (2)	0.0028 (2)	−0.00153 (19)
Mo2	0.0246 (4)	0.0173 (3)	0.0190 (3)	−0.0017 (2)	0.0040 (2)	0.00186 (19)
As1	0.0179 (6)	0.0104 (5)	0.0138 (6)	0.000	0.000	0.000
K1	0.0242 (18)	0.047 (2)	0.080 (3)	0.000	0.000	0.000
K2	0.0328 (12)	0.0281 (11)	0.0291 (11)	0.000	0.000	−0.0002 (8)
K3	0.0390 (13)	0.0324 (11)	0.0310 (11)	0.000	0.000	−0.0039 (9)
O12	0.027 (4)	0.039 (4)	0.034 (4)	0.006 (3)	0.000	0.000
O11	0.032 (5)	0.012 (4)	0.016 (4)	0.000	0.000	0.000
O10	0.036 (3)	0.035 (3)	0.042 (3)	−0.004 (2)	0.016 (2)	0.000 (2)
O9	0.029 (4)	0.038 (4)	0.031 (4)	0.000	0.000	0.005 (3)
O8	0.051 (4)	0.028 (2)	0.042 (3)	0.005 (2)	0.006 (3)	−0.006 (2)
O7	0.058 (4)	0.031 (3)	0.066 (4)	−0.013 (3)	0.021 (3)	0.006 (2)
O6	0.042 (4)	0.035 (4)	0.025 (3)	0.000	0.000	0.005 (3)
O5	0.046 (3)	0.034 (3)	0.034 (3)	0.002 (2)	0.021 (2)	0.000 (2)
O4	0.021 (5)	0.009 (4)	0.027 (4)	0.000	0.000	0.000
O3	0.030 (4)	0.025 (3)	0.025 (3)	−0.006 (3)	0.000	0.000
O2	0.032 (4)	0.027 (3)	0.027 (3)	0.000	0.000	−0.005 (3)
O1	0.029 (4)	0.047 (4)	0.026 (3)	0.003 (3)	0.000	0.000
O1W	0.039 (8)	0.012 (5)	0.150 (14)	0.000	0.000	0.000

Geometric parameters (Å, º) top

Mo1—O10	1.687 (4)	K2—O8^viii	2.979 (5)
Mo1—O8	1.697 (4)	K2—O8^ix	2.979 (5)
Mo1—O9	1.900 (3)	K2—O7ⁱⁱ	3.272 (6)
Mo1—O12	1.940 (3)	K2—O7	3.272 (6)
Mo1—O3	2.300 (4)	K2—O1W	3.297 (2)
Mo1—O4	2.409 (2)	K2—O1W	3.297 (2)
Mo1—Mo1ⁱ	3.2015 (10)	K2—Mo2ⁱⁱ	3.9915 (18)
Mo1—K1	3.859 (2)	K3—O8^x	2.756 (5)
Mo2—O7	1.692 (5)	K3—O8^xi	2.756 (5)
Mo2—O5	1.701 (4)	K3—O7^vi	2.833 (5)
Mo2—O1	1.910 (3)	K3—O7^vii	2.833 (5)
Mo2—O6	1.930 (3)	K3—O2	2.914 (6)
Mo2—O2	2.291 (4)	K3—O9	2.953 (6)
Mo2—O11	2.427 (2)	K3—O5	3.158 (5)
Mo2—Mo2ⁱⁱ	3.2050 (12)	K3—O5ⁱⁱ	3.158 (5)
Mo2—K3	3.792 (2)	K3—O6	3.168 (6)
Mo2—K2	3.9915 (18)	K3—Mo2ⁱⁱ	3.7922 (19)
Mo2—K1	4.100 (2)	K3—K2^xii	4.1672 (6)
As1—O3ⁱⁱⁱ	1.687 (6)	O12—Mo1ⁱ	1.940 (3)
As1—O3	1.687 (6)	O11—Mo2ⁱⁱ	2.427 (2)
As1—O2	1.695 (6)	O11—Mo2ⁱ	2.427 (2)
As1—O2ⁱ	1.695 (6)	O11—Mo2ⁱⁱⁱ	2.427 (2)
K1—O1^iv	2.815 (7)	O10—K2^vii	2.844 (5)
K1—O1	2.815 (7)	O9—Mo1ⁱⁱ	1.900 (3)
K1—O3	2.907 (6)	O8—K3^x	2.756 (5)
K1—O3^iv	2.907 (6)	O8—K2^xiii	2.979 (5)
K1—O10	3.183 (5)	O7—K3^vii	2.833 (5)
K1—O10^v	3.183 (5)	O6—Mo2ⁱⁱ	1.930 (3)
K1—O10^iv	3.183 (5)	O5—K2^vii	2.859 (4)
K1—O10ⁱ	3.183 (5)	O4—Mo1ⁱ	2.409 (2)
K1—O12^iv	3.298 (7)	O4—Mo1ⁱⁱ	2.409 (2)
K1—O12	3.298 (7)	O4—Mo1ⁱⁱⁱ	2.409 (2)
K1—Mo1ⁱ	3.859 (2)	O3—Mo1ⁱ	2.300 (4)
K2—O10^vi	2.844 (5)	O2—Mo2ⁱⁱ	2.291 (4)
K2—O10^vii	2.844 (5)	O1—Mo2ⁱ	1.910 (3)
K2—O5^vi	2.859 (4)	O1W—O1W	0.00 (2)
K2—O5^vii	2.859 (4)	O1W—K2ⁱ	3.297 (2)
K2—O6	2.909 (6)

O10—Mo1—O8	106.0 (2)	O10^vi—K2—O7ⁱⁱ	104.00 (13)
O10—Mo1—O9	100.1 (2)	O10^vii—K2—O7ⁱⁱ	162.64 (14)
O8—Mo1—O9	102.8 (3)	O5^vi—K2—O7ⁱⁱ	62.12 (14)
O10—Mo1—O12	103.1 (2)	O5^vii—K2—O7ⁱⁱ	111.77 (14)
O8—Mo1—O12	97.1 (2)	O6—K2—O7ⁱⁱ	51.49 (10)
O9—Mo1—O12	143.8 (2)	O8^viii—K2—O7ⁱⁱ	134.27 (14)
O10—Mo1—O3	90.3 (2)	O8^ix—K2—O7ⁱⁱ	63.37 (14)
O8—Mo1—O3	161.5 (2)	O10^vi—K2—O7	162.64 (14)
O9—Mo1—O3	82.5 (2)	O10^vii—K2—O7	104.00 (13)
O12—Mo1—O3	70.04 (19)	O5^vi—K2—O7	111.77 (14)
O10—Mo1—O4	159.8 (2)	O5^vii—K2—O7	62.12 (13)
O8—Mo1—O4	94.2 (2)	O6—K2—O7	51.49 (10)
O9—Mo1—O4	74.11 (18)	O8^viii—K2—O7	63.37 (13)
O12—Mo1—O4	74.57 (16)	O8^ix—K2—O7	134.27 (14)
O3—Mo1—O4	70.0 (2)	O7ⁱⁱ—K2—O7	90.72 (18)
O10—Mo1—Mo1ⁱ	119.71 (17)	O10^vi—K2—O1W	130.22 (18)
O8—Mo1—Mo1ⁱ	116.36 (16)	O10^vii—K2—O1W	130.22 (18)
O9—Mo1—Mo1ⁱ	109.46 (18)	O5^vi—K2—O1W	126.43 (16)
O12—Mo1—Mo1ⁱ	34.40 (15)	O5^vii—K2—O1W	126.43 (16)
O3—Mo1—Mo1ⁱ	45.89 (10)	O6—K2—O1W	79.8 (2)
O4—Mo1—Mo1ⁱ	48.35 (5)	O8^viii—K2—O1W	70.27 (14)
O10—Mo1—K1	54.24 (16)	O8^ix—K2—O1W	70.27 (14)
O8—Mo1—K1	136.12 (19)	O7ⁱⁱ—K2—O1W	64.48 (14)
O9—Mo1—K1	118.16 (19)	O7—K2—O1W	64.48 (14)
O12—Mo1—K1	58.68 (19)	O10^vi—K2—O1W	130.22 (18)
O3—Mo1—K1	48.63 (15)	O10^vii—K2—O1W	130.22 (18)
O4—Mo1—K1	110.84 (10)	O5^vi—K2—O1W	126.43 (16)
Mo1ⁱ—Mo1—K1	65.495 (16)	O5^vii—K2—O1W	126.43 (16)
O7—Mo2—O5	105.7 (2)	O6—K2—O1W	79.8 (2)
O7—Mo2—O1	104.3 (3)	O8^viii—K2—O1W	70.27 (14)
O5—Mo2—O1	99.1 (2)	O8^ix—K2—O1W	70.27 (14)
O7—Mo2—O6	96.4 (3)	O7ⁱⁱ—K2—O1W	64.48 (14)
O5—Mo2—O6	104.0 (2)	O7—K2—O1W	64.48 (14)
O1—Mo2—O6	143.4 (2)	O1W—K2—O1W	0.0 (4)
O7—Mo2—O2	160.5 (2)	O10^vi—K2—Mo2ⁱⁱ	121.40 (10)
O5—Mo2—O2	90.80 (19)	O10^vii—K2—Mo2ⁱⁱ	157.37 (11)
O1—Mo2—O2	82.6 (2)	O5^vi—K2—Mo2ⁱⁱ	61.60 (9)
O6—Mo2—O2	69.15 (19)	O5^vii—K2—Mo2ⁱⁱ	89.85 (10)
O7—Mo2—O11	93.7 (2)	O6—K2—Mo2ⁱⁱ	27.12 (6)
O5—Mo2—O11	160.5 (2)	O8^viii—K2—Mo2ⁱⁱ	127.33 (10)
O1—Mo2—O11	74.28 (19)	O8^ix—K2—Mo2ⁱⁱ	87.68 (9)
O6—Mo2—O11	74.49 (16)	O7ⁱⁱ—K2—Mo2ⁱⁱ	24.47 (9)
O2—Mo2—O11	70.33 (19)	O7—K2—Mo2ⁱⁱ	70.20 (9)
O7—Mo2—Mo2ⁱⁱ	115.4 (2)	O1W—K2—Mo2ⁱⁱ	68.26 (16)
O5—Mo2—Mo2ⁱⁱ	120.53 (17)	O1W—K2—Mo2ⁱⁱ	68.26 (16)
O1—Mo2—Mo2ⁱⁱ	109.53 (19)	O8^x—K3—O8^xi	78.9 (2)
O6—Mo2—Mo2ⁱⁱ	33.86 (14)	O8^x—K3—O7^vi	72.18 (16)
O2—Mo2—Mo2ⁱⁱ	45.62 (10)	O8^xi—K3—O7^vi	120.80 (17)
O11—Mo2—Mo2ⁱⁱ	48.69 (5)	O8^x—K3—O7^vii	120.80 (17)
O7—Mo2—K3	132.82 (18)	O8^xi—K3—O7^vii	72.18 (16)
O5—Mo2—K3	55.55 (17)	O7^vi—K3—O7^vii	80.1 (2)
O1—Mo2—K3	120.34 (19)	O8^x—K3—O2	123.14 (14)
O6—Mo2—K3	56.54 (18)	O8^xi—K3—O2	123.14 (14)
O2—Mo2—K3	50.13 (14)	O7^vi—K3—O2	115.96 (14)
O11—Mo2—K3	111.44 (10)	O7^vii—K3—O2	115.96 (14)
Mo2ⁱⁱ—Mo2—K3	65.002 (16)	O8^x—K3—O9	76.54 (14)
O7—Mo2—K2	53.2 (2)	O8^xi—K3—O9	76.54 (14)
O5—Mo2—K2	116.31 (15)	O7^vi—K3—O9	139.37 (12)
O1—Mo2—K2	141.38 (18)	O7^vii—K3—O9	139.37 (12)
O6—Mo2—K2	43.40 (17)	O2—K3—O9	62.64 (17)
O2—Mo2—K2	110.39 (11)	O8^x—K3—O5	162.95 (14)
O11—Mo2—K2	76.43 (14)	O8^xi—K3—O5	87.88 (13)
Mo2ⁱⁱ—Mo2—K2	66.329 (14)	O7^vi—K3—O5	124.43 (15)
K3—Mo2—K2	93.57 (4)	O7^vii—K3—O5	63.91 (14)
O7—Mo2—K1	111.7 (2)	O2—K3—O5	56.30 (9)
O5—Mo2—K1	62.27 (16)	O9—K3—O5	89.98 (12)
O1—Mo2—K1	36.82 (17)	O8^x—K3—O5ⁱⁱ	87.88 (13)
O6—Mo2—K1	151.01 (18)	O8^xi—K3—O5ⁱⁱ	162.95 (14)
O2—Mo2—K1	84.92 (11)	O7^vi—K3—O5ⁱⁱ	63.91 (14)
O11—Mo2—K1	109.56 (11)	O7^vii—K3—O5ⁱⁱ	124.43 (15)
Mo2ⁱⁱ—Mo2—K1	128.43 (3)	O2—K3—O5ⁱⁱ	56.30 (9)
K3—Mo2—K1	97.04 (4)	O9—K3—O5ⁱⁱ	89.98 (12)
K2—Mo2—K1	164.67 (4)	O5—K3—O5ⁱⁱ	102.71 (16)
O3ⁱⁱⁱ—As1—O3	108.6 (4)	O8^x—K3—O6	140.50 (10)
O3ⁱⁱⁱ—As1—O2	110.06 (13)	O8^xi—K3—O6	140.50 (10)
O3—As1—O2	110.06 (13)	O7^vi—K3—O6	81.10 (14)
O3ⁱⁱⁱ—As1—O2ⁱ	110.06 (13)	O7^vii—K3—O6	81.10 (14)
O3—As1—O2ⁱ	110.06 (13)	O2—K3—O6	46.54 (15)
O2—As1—O2ⁱ	108.0 (4)	O9—K3—O6	109.18 (17)
O1^iv—K1—O1	85.5 (3)	O5—K3—O6	53.87 (9)
O1^iv—K1—O3	149.7 (2)	O5ⁱⁱ—K3—O6	53.87 (9)
O1—K1—O3	64.18 (17)	O8^x—K3—Mo2	159.94 (12)
O1^iv—K1—O3^iv	64.18 (17)	O8^xi—K3—Mo2	113.71 (10)
O1—K1—O3^iv	149.7 (2)	O7^vi—K3—Mo2	110.51 (12)
O3—K1—O3^iv	146.2 (3)	O7^vii—K3—Mo2	78.84 (11)
O1^iv—K1—O10	130.02 (9)	O2—K3—Mo2	37.12 (8)
O1—K1—O10	92.05 (13)	O9—K3—Mo2	90.93 (12)
O3—K1—O10	55.77 (9)	O5—K3—Mo2	26.37 (8)
O3^iv—K1—O10	107.08 (13)	O5ⁱⁱ—K3—Mo2	76.36 (9)
O1^iv—K1—O10^v	92.05 (13)	O6—K3—Mo2	30.55 (6)
O1—K1—O10^v	130.02 (9)	O8^x—K3—Mo2ⁱⁱ	113.71 (10)
O3—K1—O10^v	107.08 (13)	O8^xi—K3—Mo2ⁱⁱ	159.94 (12)
O3^iv—K1—O10^v	55.77 (9)	O7^vi—K3—Mo2ⁱⁱ	78.84 (11)
O10—K1—O10^v	53.16 (17)	O7^vii—K3—Mo2ⁱⁱ	110.51 (12)
O1^iv—K1—O10^iv	92.05 (13)	O2—K3—Mo2ⁱⁱ	37.12 (8)
O1—K1—O10^iv	130.02 (9)	O9—K3—Mo2ⁱⁱ	90.93 (12)
O3—K1—O10^iv	107.08 (13)	O5—K3—Mo2ⁱⁱ	76.36 (9)
O3^iv—K1—O10^iv	55.77 (9)	O5ⁱⁱ—K3—Mo2ⁱⁱ	26.37 (8)
O10—K1—O10^iv	125.0 (2)	O6—K3—Mo2ⁱⁱ	30.55 (6)
O10^v—K1—O10^iv	99.94 (17)	Mo2—K3—Mo2ⁱⁱ	50.00 (3)
O1^iv—K1—O10ⁱ	130.02 (9)	O8^x—K3—K2^xii	45.54 (10)
O1—K1—O10ⁱ	92.05 (13)	O8^xi—K3—K2^xii	124.48 (12)
O3—K1—O10ⁱ	55.77 (9)	O7^vi—K3—K2^xii	51.54 (12)
O3^iv—K1—O10ⁱ	107.08 (13)	O7^vii—K3—K2^xii	131.30 (14)
O10—K1—O10ⁱ	99.94 (17)	O2—K3—K2^xii	93.13 (4)
O10^v—K1—O10ⁱ	125.0 (2)	O9—K3—K2^xii	87.96 (4)
O10^iv—K1—O10ⁱ	53.16 (17)	O5—K3—K2^xii	145.89 (10)
O1^iv—K1—O12^iv	110.18 (16)	O5ⁱⁱ—K3—K2^xii	43.27 (8)
O1—K1—O12^iv	164.35 (19)	O6—K3—K2^xii	95.00 (4)
O3—K1—O12^iv	100.17 (18)	Mo2—K3—K2^xii	119.60 (5)
O3^iv—K1—O12^iv	46.00 (15)	Mo2ⁱⁱ—K3—K2^xii	69.64 (3)
O10—K1—O12^iv	78.02 (13)	Mo1—O12—Mo1ⁱ	111.2 (3)
O10^v—K1—O12^iv	52.04 (9)	Mo1—O12—K1	91.2 (2)
O10^iv—K1—O12^iv	52.04 (9)	Mo1ⁱ—O12—K1	91.2 (2)
O10ⁱ—K1—O12^iv	78.02 (13)	Mo2ⁱⁱ—O11—Mo2ⁱ	144.6 (3)
O1^iv—K1—O12	164.35 (19)	Mo2ⁱⁱ—O11—Mo2ⁱⁱⁱ	86.75 (11)
O1—K1—O12	110.18 (16)	Mo2ⁱ—O11—Mo2ⁱⁱⁱ	82.63 (10)
O3—K1—O12	46.00 (15)	Mo2ⁱⁱ—O11—Mo2	82.63 (10)
O3^iv—K1—O12	100.17 (18)	Mo2ⁱ—O11—Mo2	86.75 (11)
O10—K1—O12	52.04 (9)	Mo2ⁱⁱⁱ—O11—Mo2	144.6 (3)
O10^v—K1—O12	78.02 (13)	Mo1—O10—K2^vii	167.1 (3)
O10^iv—K1—O12	78.02 (13)	Mo1—O10—K1	100.3 (2)
O10ⁱ—K1—O12	52.04 (9)	K2^vii—O10—K1	92.12 (14)
O12^iv—K1—O12	54.2 (2)	Mo1ⁱⁱ—O9—Mo1	121.4 (3)
O1^iv—K1—Mo1	155.37 (3)	Mo1ⁱⁱ—O9—K3	119.31 (16)
O1—K1—Mo1	91.82 (12)	Mo1—O9—K3	119.31 (16)
O3—K1—Mo1	36.42 (8)	Mo1—O8—K3^x	137.1 (3)
O3^iv—K1—Mo1	115.59 (13)	Mo1—O8—K2^xiii	129.3 (3)
O10—K1—Mo1	25.48 (8)	K3^x—O8—K2^xiii	93.14 (13)
O10^v—K1—Mo1	71.07 (10)	Mo2—O7—K3^vii	140.7 (3)
O10^iv—K1—Mo1	108.11 (12)	Mo2—O7—K2	102.3 (3)
O10ⁱ—K1—Mo1	74.48 (9)	K3^vii—O7—K2	85.77 (13)
O12^iv—K1—Mo1	73.98 (11)	Mo2ⁱⁱ—O6—Mo2	112.3 (3)
O12—K1—Mo1	30.17 (6)	Mo2ⁱⁱ—O6—K2	109.48 (19)
O1^iv—K1—Mo1ⁱ	155.37 (3)	Mo2—O6—K2	109.48 (19)
O1—K1—Mo1ⁱ	91.82 (12)	Mo2ⁱⁱ—O6—K3	92.91 (19)
O3—K1—Mo1ⁱ	36.42 (8)	Mo2—O6—K3	92.91 (19)
O3^iv—K1—Mo1ⁱ	115.59 (13)	K2—O6—K3	138.0 (2)
O10—K1—Mo1ⁱ	74.48 (9)	Mo2—O5—K2^vii	174.3 (3)
O10^v—K1—Mo1ⁱ	108.11 (12)	Mo2—O5—K3	98.1 (2)
O10^iv—K1—Mo1ⁱ	71.07 (10)	K2^vii—O5—K3	87.51 (12)
O10ⁱ—K1—Mo1ⁱ	25.48 (8)	Mo1ⁱ—O4—Mo1ⁱⁱ	146.1 (3)
O12^iv—K1—Mo1ⁱ	73.98 (11)	Mo1ⁱ—O4—Mo1	83.31 (9)
O12—K1—Mo1ⁱ	30.17 (6)	Mo1ⁱⁱ—O4—Mo1	86.93 (10)
Mo1—K1—Mo1ⁱ	49.01 (3)	Mo1ⁱ—O4—Mo1ⁱⁱⁱ	86.93 (10)
O10^vi—K2—O10^vii	60.1 (2)	Mo1ⁱⁱ—O4—Mo1ⁱⁱⁱ	83.31 (9)
O10^vi—K2—O5^vi	68.74 (15)	Mo1—O4—Mo1ⁱⁱⁱ	146.1 (3)
O10^vii—K2—O5^vi	103.14 (16)	As1—O3—Mo1ⁱ	120.9 (2)
O10^vi—K2—O5^vii	103.14 (16)	As1—O3—Mo1	120.9 (2)
O10^vii—K2—O5^vii	68.74 (15)	Mo1ⁱ—O3—Mo1	88.2 (2)
O5^vi—K2—O5^vii	72.2 (2)	As1—O3—K1	127.4 (3)
O10^vi—K2—O6	132.99 (14)	Mo1ⁱ—O3—K1	94.95 (18)
O10^vii—K2—O6	132.99 (14)	Mo1—O3—K1	94.95 (18)
O5^vi—K2—O6	64.28 (13)	As1—O2—Mo2	121.18 (19)
O5^vii—K2—O6	64.28 (13)	As1—O2—Mo2ⁱⁱ	121.18 (19)
O10^vi—K2—O8^viii	109.91 (14)	Mo2—O2—Mo2ⁱⁱ	88.8 (2)
O10^vii—K2—O8^viii	62.22 (14)	As1—O2—K3	129.7 (3)
O5^vi—K2—O8^viii	160.37 (15)	Mo2—O2—K3	92.75 (17)
O5^vii—K2—O8^viii	89.59 (13)	Mo2ⁱⁱ—O2—K3	92.75 (17)
O6—K2—O8^viii	114.80 (11)	Mo2—O1—Mo2ⁱ	121.6 (3)
O10^vi—K2—O8^ix	62.22 (14)	Mo2—O1—K1	119.19 (17)
O10^vii—K2—O8^ix	109.91 (14)	Mo2ⁱ—O1—K1	119.19 (17)
O5^vi—K2—O8^ix	89.59 (13)	O1W—O1W—K2ⁱ	0 (10)
O5^vii—K2—O8^ix	160.37 (15)	O1W—O1W—K2	0 (10)
O6—K2—O8^ix	114.80 (11)	K2ⁱ—O1W—K2	174.9 (4)
O8^viii—K2—O8^ix	107.32 (19)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1···O12^xiv	0.82 (9)	2.06 (9)	2.831 (11)	157 (9)
O11—H4···O1W	0.87 (11)	1.81 (11)	2.684 (13)	180 (1)

Symmetry code: (xiv) −x+1/2, y−1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	K₅[Mo₈O₂₄(OH)₂(AsO₄)]·2H₂O
M_r	1553.95
Crystal system, space group	Orthorhombic, Cmcm
Temperature (K)	293
a, b, c (Å)	8.3024 (12), 23.008 (3), 15.279 (2)
V (Å³)	2918.6 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	5.28
Crystal size (mm)	0.20 × 0.18 × 0.16

Data collection
Diffractometer	Rigaku R-AXIS RAPID diffractometer
Absorption correction	Multi-scan (ABSCOR; Higashi, 1995)
T_min, T_max	0.418, 0.486
No. of measured, independent and observed [I > 2σ(I)] reflections	12346, 1606, 1216
R_int	0.048
(sin θ/λ)_max (Å⁻¹)	0.618

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.098, 1.07
No. of reflections	1606
No. of parameters	133
H-atom treatment	Only H-atom coordinates refined
Δρ_max, Δρ_min (e Å⁻³)	1.99, −0.72

Computer programs: RAPID-AUTO (Rigaku, 1998), SHELXS97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), DIAMOND (Brandenburg, 2007), SHELXL97 (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1···O12ⁱ	0.82 (9)	2.06 (9)	2.831 (11)	157 (9)
O11—H4···O1W	0.87 (11)	1.81 (11)	2.684 (13)	180.000 (1)

Symmetry code: (i) −x+1/2, y−1/2, −z+1/2.

Acknowledgements

This work was supported financially by the National Natural Science Foundation of Heilongjiang Province (Nos. B200901 and B200917).

References

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