Tetra­potassium cis-dioxido-trans-bis­(sulfato-κO)sulfato(κ2O,O′)molybdate(VI)

Schäffer, S.J.C.; Berg, R.W.

doi:10.1107/S1600536808003851

inorganic compounds

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Volume 64| Part 3| March 2008| Page i20

doi:10.1107/S1600536808003851

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Tetrapotassium cis-dioxido-trans-bis(sulfato-κO)sulfato(κ²O,O′)molybdate(VI)

Susan J. Cline Schäffer ^a ‡ and Rolf W. Berg ^a ^*

^aThe Technical University of Denmark, Department of Chemistry, Building 207, DK-2800 Lyngby, Denmark
^*Correspondence e-mail: su@tgy.dk

(Received 2 January 2008; accepted 5 February 2008; online 13 February 2008)

The title compound, K₄[Mo^VIO₂(SO₄)₃], was precipitated from a melt of molybdenum(VI) oxide and potassium sulfate in potassium disulfate. The compound contains monomeric [Mo^VIO₂(SO₄)₃]⁴⁻ anions, with the Mo^VI atom, both oxide ligands, and the S atom and both ligating O atoms of the bidentate sulfate group lying on a crystallographic mirror plane. One of the potassium cations is nine-coordinate, while the other is eight-coordinate.

Related literature

For related literature, see: Topsøe & Nielsen (1947 ); Berg & Thorup (2005 ); Borup et al. (1990 ); Nørbygaard et al. (1998 ); Nielsen et al. (1993 ); Rasmussen et al. (2003 ); Salles et al. (1996 ); Schäffer & Berg (2005 ); Tamasi & Cini (2003 ).

Experimental

Crystal data

K₄[MoO₂(SO₄)₃]
M_r = 572.52
Orthorhombic, P n m a
a = 7.5931 (5) Å
b = 17.1276 (11) Å
c = 10.5132 (7) Å
V = 1367.26 (16) Å³
Z = 4
Mo Kα radiation
μ = 2.71 mm⁻¹
T = 120 (2) K
0.28 × 0.18 × 0.07 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: Gaussian (XPREP; Bruker, 2002 ) T_min = 0.512, T_max = 0.684
16179 measured reflections
1693 independent reflections
1681 reflections with I > 2σ(I)
R_int = 0.018

Refinement

R[F² > 2σ(F²)] = 0.016
wR(F²) = 0.041
S = 1.11
1693 reflections
110 parameters
Δρ_max = 0.59 e Å⁻³
Δρ_min = −0.46 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Mo1—O1	1.6889 (18)
Mo1—O2	1.6883 (18)
Mo1—O3	2.2665 (17)
Mo1—O4	2.1837 (16)
Mo1—O6	2.0365 (12)
K1—O5ⁱ	2.6408 (12)
K1—O8ⁱⁱ	3.2305 (14)
K2—O8ⁱⁱⁱ	2.7005 (14)
K2—O6^iv	3.0239 (13)

O2—Mo1—O1	105.77 (10)
O2—Mo1—O6	98.04 (4)
O1—Mo1—O6	94.84 (4)
O6—Mo1—O6^v	158.22 (7)
O2—Mo1—O4	155.71 (8)
O1—Mo1—O4	98.52 (8)
O6—Mo1—O4	79.65 (3)
O2—Mo1—O3	92.29 (8)
O1—Mo1—O3	161.94 (8)
O6—Mo1—O3	82.38 (3)
O4—Mo1—O3	63.43 (6)
Symmetry codes: (i) $[x-{\script{1\over 2}}, y, -z-{\script{1\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, -y, z-{\script{1\over 2}}]$ ; (iii) $[x+{\script{1\over 2}}, y, -z+{\script{1\over 2}}]$ ; (iv) $[x-{\script{1\over 2}}, y, -z+{\script{1\over 2}}]$ ; (v) $[x, -y+{\script{1\over 2}}, z]$ .

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808003851/bi2277sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808003851/bi2277Isup2.hkl

checkCIF report

Comment top

Efforts to improve the industrial vanadium-based sulfuric acid catalyst (Topsøe & Nielsen, 1947) have led to investigations of potassium disulfate's use as a suitable solvent for the production of new sulfate-containing catalysts. Many of the previously reported sulfato compounds precipitated from melts of potassium disulfate contain polymeric anions (Nørbygaard et al., 1998, Berg & Thorup, 2005), while some contain dimers (Nielsen et al., 1993, Rasmussen et al., 2003, Schäffer & Berg, 2005). Monomers such as that in the title compound (Fig. 1) are less common (Borup et al., 1990).

The coordination sphere of the Mo^VI atom contains two oxido ligands, two terminally bound sulfato ligands, and a bidentate sulfato ligand. Because of the bidentate ligand, the coordination sphere angles (see Table 1) in the mirror plane are grossly distorted from octahedral. The O3—Mo1—O4 angle is only 63.43 (6)°, while the O1—Mo1—O2 angle opposite to it is 105.77 (10)°. Deviations of 10° or less are found for the other angles between cis O atoms. The Mo=O bond distances are nearly equivalent (1.6883 (18)Å & 1.6889 (18) Å), which is expected since both bonds are trans to O atoms in the bidentate sulfato ligand. The Mo—O distance to the terminal sulfato [Mo1—O6] is slightly shorter than those to the bidentate sulfato ligand [Mo1—O3 and Mo1—O4]. The Mo—O distances compare well with previously reported values (Salles et al., 1996, Nørbygaard et al., 1998).

The S—O bond distances of 1.5044 (17)–1.5532 (17)Å involving O bound to Mo are longer than the terminal S—O bond lengths of 1.4497–1.4621 (12) Å, an effect typical for sulfato complexes of many different transition metal centers (Borup et al., 1990, Nielsen et al., 1993, Berg & Thorup, 2005). The sulfato ligands have approximately tetrahedral geometry. The angles vary from 101.14° for O3—S1—O4 to 114.68 (10)° for O5—S1—O5ⁱ [symmetry code (i): x, 1/2 - y, z]; both extremes involve the bidentate sulfato ligand. Five of the eight remaining independent O—S—O angles deviate by less than 2° from ideal. The potassium cation, K1, is nine-coordinate, while K2 is eight-coordinate. The K—O distances range from 2.6408 to 3.2305 (14) Å.

Related literature top

For related literature, see: Topsøe & Nielsen (1947); Berg & Thorup (2005); Borup et al. (1990); Nørbygaard et al. (1998); Nielsen et al. (1993); Rasmussen et al. (2003); Salles et al. (1996); Schäffer & Berg (2005); Tamasi & Cini (2003).

Experimental top

Crystals were grown from a melt of 28.0 mol% molybdenum(VI) oxide, 43.9 mol% potassium sulfate, and 28.1 mol% potassium disulfate, using a method described previously (Nørbygaard et al., 1998).

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The [Mo^VIO₂(SO₄)₃]^4- anion and four K⁺ cations, showing displacement ellipsoids at 50% probability.
	Fig. 2. The crystal packing, viewed along the a axis.

Tetrapotassium cis-dioxido-trans-bis(sulfato-\kO)sulfato(κ²O,O')molybdate(VI) top

Crystal data top

K₄[MoO₂(SO₄)₃]	F(000) = 1112
M_r = 572.52	D_x = 2.781 Mg m⁻³
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 9999 reflections
a = 7.5931 (5) Å	θ = 2.3–28.0°
b = 17.1276 (11) Å	µ = 2.71 mm⁻¹
c = 10.5132 (7) Å	T = 120 K
V = 1367.26 (16) Å³	Tabular, colorless
Z = 4	0.28 × 0.18 × 0.08 mm

Data collection top

Bruker SMART APEX CCD diffractometer	1693 independent reflections
Radiation source: normal-focus sealed tube	1681 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.019
ω scans	θ_max = 28.0°, θ_min = 2.3°
Absorption correction: gaussian (XPREP; Bruker, 2002)	h = −9→10
T_min = 0.512, T_max = 0.684	k = −22→22
16179 measured reflections	l = −13→13

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)] = 0.016	w = 1/[σ²(F_o²) + (0.0174P)² + 1.7854P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.041	(Δ/σ)_max < 0.001
S = 1.11	Δρ_max = 0.59 e Å⁻³
1693 reflections	Δρ_min = −0.46 e Å⁻³
110 parameters	Extinction correction: SHELXTL (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00164 (15)

Crystal data top

K₄[MoO₂(SO₄)₃]	V = 1367.26 (16) Å³
M_r = 572.52	Z = 4
Orthorhombic, Pnma	Mo Kα radiation
a = 7.5931 (5) Å	µ = 2.71 mm⁻¹
b = 17.1276 (11) Å	T = 120 K
c = 10.5132 (7) Å	0.28 × 0.18 × 0.08 mm

Data collection top

Bruker SMART APEX CCD diffractometer	1693 independent reflections
Absorption correction: gaussian (XPREP; Bruker, 2002)	1681 reflections with I > 2σ(I)
T_min = 0.512, T_max = 0.684	R_int = 0.019
16179 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.016	110 parameters
wR(F²) = 0.041	0 restraints
S = 1.11	Δρ_max = 0.59 e Å⁻³
1693 reflections	Δρ_min = −0.46 e Å⁻³

Special details top

Experimental. Five series of frames were filtered for statistical outliers then corrected for absorption using XPREP in SHELXTL (Sheldrick, 2008) before using SAINT & SADABS (Bruker, 2002) to sort, merge, and scale the combined data. A series of identical frames was collected twice during the experiment to monitor decay, and none was observed.

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 (Å²) top

	x	y	z	U_iso*/U_eq
K1	0.43682 (4)	0.08865 (2)	−0.24076 (3)	0.01208 (8)
K2	0.25655 (5)	0.10844 (2)	0.39352 (3)	0.01644 (9)
Mo1	0.32312 (3)	0.2500	0.065899 (18)	0.00961 (7)
S1	0.62301 (7)	0.2500	−0.09790 (5)	0.00926 (11)
S2	0.23382 (5)	0.06574 (2)	0.06161 (3)	0.00949 (9)
O1	0.3105 (3)	0.2500	0.22628 (17)	0.0209 (4)
O2	0.1129 (2)	0.2500	0.0135 (2)	0.0219 (4)
O3	0.4316 (2)	0.2500	−0.13493 (15)	0.0124 (3)
O4	0.6095 (2)	0.2500	0.04687 (15)	0.0102 (3)
O5	0.70888 (16)	0.17874 (7)	−0.13903 (11)	0.0135 (2)
O6	0.36968 (15)	0.13324 (7)	0.05145 (11)	0.0134 (2)
O7	0.16034 (17)	0.05557 (8)	−0.06586 (11)	0.0161 (3)
O8	0.10253 (17)	0.08813 (8)	0.15593 (12)	0.0184 (3)
O9	0.33322 (16)	−0.00276 (7)	0.10186 (13)	0.0176 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.01082 (17)	0.01361 (16)	0.01182 (16)	0.00149 (12)	−0.00089 (12)	0.00023 (12)
K2	0.02176 (19)	0.01335 (17)	0.01422 (17)	0.00508 (14)	0.00204 (14)	−0.00023 (13)
Mo1	0.00891 (10)	0.00789 (10)	0.01203 (11)	0.000	0.00220 (7)	0.000
S1	0.0105 (2)	0.0077 (2)	0.0096 (2)	0.000	0.0013 (2)	0.000
S2	0.01081 (18)	0.00829 (17)	0.00938 (18)	−0.00132 (14)	0.00002 (13)	0.00071 (13)
O1	0.0304 (11)	0.0172 (9)	0.0150 (9)	0.000	0.0080 (8)	0.000
O2	0.0117 (8)	0.0178 (9)	0.0364 (11)	0.000	−0.0020 (8)	0.000
O3	0.0119 (8)	0.0139 (8)	0.0115 (7)	0.000	−0.0019 (6)	0.000
O4	0.0115 (8)	0.0102 (7)	0.0089 (7)	0.000	0.0001 (6)	0.000
O5	0.0158 (6)	0.0095 (5)	0.0153 (6)	0.0017 (4)	0.0044 (5)	−0.0012 (4)
O6	0.0116 (5)	0.0088 (5)	0.0197 (6)	−0.0019 (4)	0.0022 (5)	−0.0001 (4)
O7	0.0187 (6)	0.0186 (6)	0.0111 (6)	−0.0037 (5)	−0.0034 (4)	0.0017 (4)
O8	0.0163 (6)	0.0201 (6)	0.0187 (6)	−0.0045 (5)	0.0072 (5)	−0.0055 (5)
O9	0.0181 (6)	0.0116 (6)	0.0232 (6)	−0.0002 (5)	−0.0046 (5)	0.0058 (5)

Geometric parameters (Å, º) top

Mo1—O1	1.6889 (18)	K2—O8^vi	2.7005 (14)
Mo1—O2	1.6883 (18)	K2—O4^vii	2.7419 (8)
Mo1—O3	2.2665 (17)	K2—O8	2.7799 (14)
Mo1—O4	2.1837 (16)	K2—O5^vii	2.8710 (13)
Mo1—O6	2.0365 (12)	K2—O7^viii	2.9106 (14)
Mo1—O6ⁱ	2.0365 (12)	K2—O9^viii	2.9220 (14)
S1—O3	1.5044 (17)	K2—O1	3.0229 (11)
S1—O4	1.5254 (16)	K2—O6^vii	3.0239 (13)
S1—O5	1.4497 (12)	O1—K2ⁱ	3.0229 (11)
S1—O5ⁱ	1.4497 (12)	O3—K1ⁱ	2.9794 (7)
S2—O6	1.5532 (12)	O4—K2^ix	2.7419 (8)
S2—O7	1.4621 (12)	O4—K2^vi	2.7419 (8)
S2—O8	1.4575 (13)	O5—K1ⁱⁱⁱ	2.6408 (12)
S2—O9	1.4577 (12)	O5—K2^vi	2.8710 (13)
K1—O5ⁱⁱ	2.6408 (12)	O6—K2^vi	3.0239 (13)
K1—O7ⁱⁱⁱ	2.7083 (12)	O7—K1ⁱⁱ	2.7083 (12)
K1—O9^iv	2.7102 (12)	O7—K2^v	2.9106 (14)
K1—O5	2.7915 (13)	O8—K2^vii	2.7005 (14)
K1—O7	2.8476 (13)	O8—K1^viii	3.2305 (14)
K1—O3	2.9794 (7)	O9—K1^iv	2.7102 (12)
K1—O9^v	3.0176 (13)	O9—K2^v	2.9220 (13)
K1—O6	3.2064 (12)	O9—K1^viii	3.0176 (13)
K1—O8^v	3.2305 (14)

O5ⁱⁱ—K1—O7ⁱⁱⁱ	100.00 (4)	O1—Mo1—O6ⁱ	94.84 (4)
O5ⁱⁱ—K1—O9^iv	175.76 (4)	O6—Mo1—O6ⁱ	158.22 (7)
O7ⁱⁱⁱ—K1—O9^iv	83.52 (4)	O2—Mo1—O4	155.71 (8)
O5ⁱⁱ—K1—O5	110.20 (4)	O1—Mo1—O4	98.52 (8)
O7ⁱⁱⁱ—K1—O5	86.53 (4)	O6—Mo1—O4	79.65 (3)
O9^iv—K1—O5	67.47 (4)	O6ⁱ—Mo1—O4	79.65 (3)
O5ⁱⁱ—K1—O7	86.68 (4)	O2—Mo1—O3	92.29 (8)
O7ⁱⁱⁱ—K1—O7	154.84 (5)	O1—Mo1—O3	161.94 (8)
O9^iv—K1—O7	91.09 (4)	O6—Mo1—O3	82.38 (3)
O5—K1—O7	114.09 (4)	O6ⁱ—Mo1—O3	82.38 (3)
O5ⁱⁱ—K1—O3	68.16 (4)	O4—Mo1—O3	63.43 (6)
O7ⁱⁱⁱ—K1—O3	118.86 (4)	O3—S1—O4	101.14 (9)
O9^iv—K1—O3	108.11 (4)	O5—S1—O5ⁱ	114.68 (10)
O5—K1—O3	49.76 (4)	O5—S1—O3	110.93 (6)
O7—K1—O3	86.20 (4)	O5ⁱ—S1—O3	110.93 (6)
O5ⁱⁱ—K1—O9^v	64.98 (4)	O5—S1—O4	109.14 (6)
O7ⁱⁱⁱ—K1—O9^v	84.97 (4)	O5ⁱ—S1—O4	109.14 (6)
O9^iv—K1—O9^v	117.94 (5)	O8—S2—O9	111.62 (8)
O5—K1—O9^v	169.23 (4)	O8—S2—O7	113.20 (8)
O7—K1—O9^v	75.89 (4)	O9—S2—O7	111.58 (8)
O3—K1—O9^v	130.39 (4)	O8—S2—O6	107.77 (7)
O5ⁱⁱ—K1—O6	102.42 (4)	O9—S2—O6	105.97 (7)
O7ⁱⁱⁱ—K1—O6	150.31 (4)	O7—S2—O6	106.20 (7)
O9^iv—K1—O6	73.47 (4)	Mo1—O1—K2ⁱ	126.04 (3)
O5—K1—O6	67.60 (3)	Mo1—O1—K2	126.04 (3)
O7—K1—O6	46.49 (3)	K2ⁱ—O1—K2	106.66 (6)
O3—K1—O6	54.49 (4)	S1—O3—Mo1	96.32 (8)
O9^v—K1—O6	122.24 (3)	S1—O3—K1	94.81 (4)
O5ⁱⁱ—K1—O8^v	109.03 (4)	Mo1—O3—K1	110.65 (3)
O7ⁱⁱⁱ—K1—O8^v	67.02 (4)	S1—O3—K1ⁱ	94.81 (4)
O9^iv—K1—O8^v	74.46 (4)	Mo1—O3—K1ⁱ	110.65 (3)
O5—K1—O8^v	135.67 (3)	K1—O3—K1ⁱ	136.12 (6)
O7—K1—O8^v	87.85 (4)	S1—O4—Mo1	99.11 (8)
O3—K1—O8^v	173.55 (4)	S1—O4—K2^ix	101.58 (4)
O9^v—K1—O8^v	45.24 (3)	Mo1—O4—K2^ix	112.62 (4)
O6—K1—O8^v	122.05 (3)	S1—O4—K2^vi	101.58 (4)
O8^vi—K2—O4^vii	123.65 (4)	Mo1—O4—K2^vi	112.62 (4)
O8^vi—K2—O8	102.72 (3)	K2^ix—O4—K2^vi	124.32 (6)
O4^vii—K2—O8	98.32 (4)	S1—O5—K1ⁱⁱⁱ	158.35 (7)
O8^vi—K2—O5^vii	110.47 (4)	S1—O5—K1	104.29 (6)
O4^vii—K2—O5^vii	51.12 (4)	K1ⁱⁱⁱ—O5—K1	88.78 (4)
O8—K2—O5^vii	143.83 (4)	S1—O5—K2^vi	98.14 (6)
O8^vi—K2—O7^viii	72.12 (4)	K1ⁱⁱⁱ—O5—K2^vi	95.88 (4)
O4^vii—K2—O7^viii	155.26 (4)	K1—O5—K2^vi	101.88 (4)
O8—K2—O7^viii	95.87 (4)	S2—O6—Mo1	127.63 (7)
O5^vii—K2—O7^viii	107.47 (3)	S2—O6—K2^vi	121.83 (6)
O8^vi—K2—O9^viii	106.95 (4)	Mo1—O6—K2^vi	107.00 (5)
O4^vii—K2—O9^viii	106.35 (4)	S2—O6—K1	89.66 (5)
O8—K2—O9^viii	119.86 (4)	Mo1—O6—K1	109.45 (5)
O5^vii—K2—O9^viii	63.67 (3)	K2^vi—O6—K1	89.74 (3)
O7^viii—K2—O9^viii	48.91 (3)	S2—O7—K1ⁱⁱ	154.47 (8)
O8^vi—K2—O1	81.93 (5)	S2—O7—K1	106.67 (6)
O4^vii—K2—O1	58.59 (4)	K1ⁱⁱ—O7—K1	86.31 (3)
O8—K2—O1	68.58 (4)	S2—O7—K2^v	99.59 (6)
O5^vii—K2—O1	101.75 (4)	K1ⁱⁱ—O7—K2^v	103.16 (4)
O7^viii—K2—O1	146.11 (4)	K1—O7—K2^v	86.41 (4)
O9^viii—K2—O1	164.67 (4)	S2—O8—K2^vii	124.63 (7)
O8^vi—K2—O6^vii	179.32 (4)	S2—O8—K2	110.89 (7)
O4^vii—K2—O6^vii	55.70 (4)	K2^vii—O8—K2	124.48 (5)
O8—K2—O6^vii	77.34 (4)	S2—O8—K1^viii	92.60 (6)
O5^vii—K2—O6^vii	69.31 (3)	K2^vii—O8—K1^viii	95.48 (4)
O7^viii—K2—O6^vii	108.55 (3)	K2—O8—K1^viii	81.61 (4)
O9^viii—K2—O6^vii	73.56 (3)	S2—O9—K1^iv	157.94 (8)
O1—K2—O6^vii	97.48 (4)	S2—O9—K2^v	99.22 (6)
O2—Mo1—O1	105.77 (10)	K1^iv—O9—K2^v	102.59 (4)
O2—Mo1—O6	98.04 (4)	S2—O9—K1^viii	101.52 (6)
O1—Mo1—O6	94.84 (4)	K1^iv—O9—K1^viii	82.98 (3)
O2—Mo1—O6ⁱ	98.04 (4)	K2^v—O9—K1^viii	87.16 (3)

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

Experimental details

Crystal data
Chemical formula	K₄[MoO₂(SO₄)₃]
M_r	572.52
Crystal system, space group	Orthorhombic, Pnma
Temperature (K)	120
a, b, c (Å)	7.5931 (5), 17.1276 (11), 10.5132 (7)
V (Å³)	1367.26 (16)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.71
Crystal size (mm)	0.28 × 0.18 × 0.08

Data collection
Diffractometer	Bruker SMART APEX CCD diffractometer
Absorption correction	Gaussian (XPREP; Bruker, 2002)
T_min, T_max	0.512, 0.684
No. of measured, independent and observed [I > 2σ(I)] reflections	16179, 1693, 1681
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.660

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.016, 0.041, 1.11
No. of reflections	1693
No. of parameters	110
Δρ_max, Δρ_min (e Å⁻³)	0.59, −0.46

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top

Mo1—O1	1.6889 (18)	S2—O6	1.5532 (12)
Mo1—O2	1.6883 (18)	S2—O7	1.4621 (12)
Mo1—O3	2.2665 (17)	S2—O8	1.4575 (13)
Mo1—O4	2.1837 (16)	S2—O9	1.4577 (12)
Mo1—O6	2.0365 (12)	K1—O5ⁱ	2.6408 (12)
S1—O3	1.5044 (17)	K1—O8ⁱⁱ	3.2305 (14)
S1—O4	1.5254 (16)	K2—O8ⁱⁱⁱ	2.7005 (14)
S1—O5	1.4497 (12)	K2—O6^iv	3.0239 (13)

O2—Mo1—O1	105.77 (10)	O2—Mo1—O3	92.29 (8)
O2—Mo1—O6	98.04 (4)	O1—Mo1—O3	161.94 (8)
O1—Mo1—O6	94.84 (4)	O6—Mo1—O3	82.38 (3)
O6—Mo1—O6^v	158.22 (7)	O4—Mo1—O3	63.43 (6)
O2—Mo1—O4	155.71 (8)	O3—S1—O4	101.14 (9)
O1—Mo1—O4	98.52 (8)	O5—S1—O5^v	114.68 (10)
O6—Mo1—O4	79.65 (3)

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

Footnotes

‡Current address: Tårnby Gymnasium & HF, Tejn Allé 5, DK-2770 Kastrup, Denmark.

Acknowledgements

The authors thank Astrid Schønberg and Bodil Holten for help and advice.

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