Redetermination of diammonium thio­molybdate

Abstract

In contrast to the previous structure determinations of the title structure, (NH₄)₂[MoS₄], the present determination at 173 K localized the positions of the H atoms. The title structure belongs to the β-K₂SO₄ family and all the ions are located on crystallographic mirror planes. The ions are held together by N—H⋯S hydrogen bonds (some of which are bifurcated), forming a three-dimensional network. One of the N atoms has nine contacts to the S atoms shorter than 4 Å, and the other has ten.

Related literature

For preparation of the title compound, see: Herzog et al. (1981 ▶). For structures of the β-K₂SO₄ family, see: Fábry & Pérez-Mato (1994 ▶). For other structure determinations of the title compound, see: Lapasset et al. (1976 ▶); Schäfer et al. (1964 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶).

Experimental

Crystal data

• (NH₄)₂[MoS₄]

• M _r = 260.26

• Orthorhombic,

• a = 9.5867 (4) Å

• b = 6.9451 (4) Å

• c = 12.2005 (5) Å

• V = 812.32 (7) ų

• Z = 4

• Mo Kα radiation

• μ = 2.55 mm⁻¹

• T = 173 K

• 0.25 × 0.24 × 0.11 mm

Data collection

• Stoe IPDS II two-circle diffractometer

• Absorption correction: multi-scan (MULABS; Spek, 2009 ▶; Blessing, 1995 ▶) T _min = 0.569, T _max = 0.767

• 14872 measured reflections

• 859 independent reflections

• 833 reflections with I > 2σ(I)

• R _int = 0.072

Refinement

• R[F ² > 2σ(F ²)] = 0.022

• wR(F ²) = 0.060

• S = 1.19

• 859 reflections

• 61 parameters

• 6 restraints

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.51 e Å⁻³

• Δρ_min = −0.88 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯S1i	0.86 (2)	2.76 (4)	3.491 (3)	144 (6)
N1—H1B⋯S1ii	0.88 (2)	2.92 (5)	3.607 (3)	135 (5)
N1—H1B⋯S3	0.88 (2)	2.87 (3)	3.497 (3)	129 (3)
N1—H1B⋯S3iii	0.88 (2)	2.87 (3)	3.497 (3)	129 (3)
N1—H1C⋯S3iv	0.88 (2)	2.76 (3)	3.550 (3)	150 (4)
N1—H1C⋯S3iv	0.88 (2)	2.76 (3)	3.550 (3)	150 (4)
N2—H2C⋯S3v	0.88 (2)	2.65 (3)	3.405 (2)	144 (4)
N2—H2A⋯S3vi	0.88 (2)	2.76 (2)	3.481 (2)	140 (1)
N2—H2A⋯S3vii	0.88 (2)	2.76 (2)	3.481 (2)	140 (1)
N2—H2B⋯S1	0.88 (2)	2.61 (4)	3.414 (3)	153 (6)
N2—H2B⋯S2	0.88 (2)	2.70 (6)	3.250 (3)	122 (5)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

supplementary crystallographic information

Comment

The crystal structure of the title compound, (NH₄)₂MoS₄, previously determined using Weissenberg exposures (Schäfer et al., 1964) and using a point detector diffractometer (Lapasset et al., 1976) has been redetermined at low temperature since the two previous structure determinations did not include the positions of the H atoms.

The crystal structure belongs to the β-K₂SO₄ family (Fábry & Pérez-Mato, 1994). The anions and cations are held together by N—H···S hydrogen bonds forming a three-dimensional network involving all H atoms.

Experimental

The ammonium tetrathiomolybdate (NH₄)₂MoS₄ was synthesized by the reaction from (NH₄)₆Mo₇O₂₄^.4H₂O with H₂S in the presence of NH₃ (Herzog et al., 1981) as shown by the equation:

(NH₄)₆Mo₇O₂₄ + 28 H₂S + 8 NH₃→ 7(NH₄)₂MoS₄ + 24 H₂O.

H₂S was bubbled for 30 minutes through a solution of 4.94 g (4.0 mmol) (NH₄)₆Mo₇O₂₄^.4H₂O in 50 ml aqueous ammonia. At first the reaction solution became yellow then the colour changed from yellow towards red. The red colour indicated the end of the reaction (Herzog et al., 1981). X-ray quality crystals of (NH₄)₂MoS₄ were grown from the reaction solution at ambient temperature. The crystals are pleochroic, changing colour from red to green according to the view angle.

Refinement

Hydrogen atoms were located in a difference Fourier map and refined isotropically. The N—H distances were restrained to 0.878 (20) Å. The value 0.878Å has been retrieved from the structures XUDGET, TERNOT, TEJMUQ, TEJMOK, KOLKAY, KEVVEN, ICOMUI contained in the Cambridge Crystallographic Database (Version 5.31; Allen, 2002). The condition of the search in the Cambridge Crystallographic Database: The structures contained [NH₄]⁺, K was the possibly heaviest atom in the structure, and the structures have been determined with R-factor 〈 0.03.

Figures

Fig. 1.

A view of the three molecules in the asymmetric unit of the title compound, with the atom-numbering scheme. The displacement ellipsoids are drawn at the 50% probability level and the H atoms are shown as small spheres of arbitrary radii.

Crystal data

(NH4)2[MoS4]	F(000) = 512
Mr = 260.26	Dx = 2.128 Mg m−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 14093 reflections
a = 9.5867 (4) Å	θ = 2.7–26.4°
b = 6.9451 (4) Å	µ = 2.55 mm−1
c = 12.2005 (5) Å	T = 173 K
V = 812.32 (7) Å3	Plate, dark green
Z = 4	0.25 × 0.24 × 0.11 mm

Data collection

Stoe IPDS II two-circle diffractometer	859 independent reflections
Radiation source: fine-focus sealed tube	833 reflections with I > 2σ(I)
graphite	Rint = 0.072
ω scans	θmax = 25.9°, θmin = 2.7°
Absorption correction: multi-scan (MULABS; Spek, 2009; Blessing, 1995)	h = −11→11
Tmin = 0.569, Tmax = 0.767	k = −8→8
14872 measured reflections	l = −14→15

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.022	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.060	w = 1/[σ2(Fo2) + (0.0377P)2 + 0.2462P] where P = (Fo2 + 2Fc2)/3
S = 1.19	(Δ/σ)max < 0.001
859 reflections	Δρmax = 0.51 e Å−3
61 parameters	Δρmin = −0.88 e Å−3
6 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0173 (13)

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
Mo1	0.25414 (2)	0.7500	0.42734 (2)	0.01490 (16)
S1	0.03014 (7)	0.7500	0.38769 (6)	0.0229 (2)
S2	0.28425 (9)	0.7500	0.60460 (7)	0.0246 (2)
S3	0.35338 (5)	0.49616 (7)	0.35742 (5)	0.0259 (2)
N1	0.6660 (3)	0.7500	0.3880 (2)	0.0257 (6)
H1A	0.746 (4)	0.7500	0.355 (5)	0.072 (19)*
H1B	0.590 (4)	0.7500	0.347 (4)	0.089 (19)*
H1C	0.665 (5)	0.850 (5)	0.433 (3)	0.114 (18)*
N2	−0.0471 (3)	0.7500	0.6609 (2)	0.0223 (5)
H2A	−0.002 (5)	0.7500	0.723 (3)	0.09 (2)*
H2B	0.003 (6)	0.7500	0.600 (3)	0.10 (2)*
H2C	−0.097 (5)	0.644 (5)	0.656 (4)	0.114 (16)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Mo1	0.0146 (2)	0.0149 (2)	0.0152 (2)	0.000	0.00038 (8)	0.000
S1	0.0161 (4)	0.0297 (4)	0.0228 (4)	0.000	−0.0034 (3)	0.000
S2	0.0214 (4)	0.0349 (4)	0.0175 (4)	0.000	−0.0024 (3)	0.000
S3	0.0235 (3)	0.0196 (3)	0.0346 (3)	0.00079 (18)	0.0062 (2)	−0.0074 (2)
N1	0.0235 (14)	0.0268 (14)	0.0267 (15)	0.000	−0.0028 (11)	0.000
N2	0.0219 (13)	0.0258 (13)	0.0193 (13)	0.000	0.0030 (10)	0.000

Geometric parameters (Å, °)

Mo1—S3i	2.1773 (5)	N1—H1B	0.88 (2)
Mo1—S3	2.1773 (5)	N1—H1C	0.883 (19)
Mo1—S2	2.1818 (9)	N2—H2A	0.88 (2)
Mo1—S1	2.2013 (8)	N2—H2B	0.88 (2)
N1—H1A	0.86 (2)	N2—H2C	0.879 (19)
S3i—Mo1—S3	108.13 (3)	H1A—N1—H1B	118 (6)
S3i—Mo1—S2	109.30 (2)	H1A—N1—H1C	107 (4)
S3—Mo1—S2	109.30 (2)	H1B—N1—H1C	110 (3)
S3i—Mo1—S1	109.885 (19)	H2A—N2—H2B	117 (5)
S3—Mo1—S1	109.885 (19)	H2A—N2—H2C	109 (3)
S2—Mo1—S1	110.30 (3)	H2B—N2—H2C	103 (3)

Symmetry codes: (i) x, −y+3/2, z.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···S1ii	0.86 (2)	2.76 (4)	3.491 (3)	144 (6)
N1—H1B···S1iii	0.88 (2)	2.92 (5)	3.607 (3)	135 (5)
N1—H1B···S3	0.88 (2)	2.87 (3)	3.497 (3)	129 (3)
N1—H1B···S3i	0.88 (2)	2.87 (3)	3.497 (3)	129 (3)
N1—H1C···S3iv	0.88 (2)	2.76 (3)	3.550 (3)	150 (4)
N1—H1C···S3iv	0.88 (2)	2.76 (3)	3.550 (3)	150 (4)
N2—H2C···S3v	0.88 (2)	2.65 (3)	3.405 (2)	144 (4)
N2—H2A···S3vi	0.88 (2)	2.76 (2)	3.481 (2)	140 (1)
N2—H2A···S3vii	0.88 (2)	2.76 (2)	3.481 (2)	140 (1)
N2—H2B···S1	0.88 (2)	2.61 (4)	3.414 (3)	153 (6)
N2—H2B···S2	0.88 (2)	2.70 (6)	3.250 (3)	122 (5)

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