Dicaesium hexa­mercury hepta­sulfide

Bugaris, D.E.; Ibers, J.A.

doi:10.1107/S1600536808023477

inorganic compounds

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ISSN: 2056-9890

Volume 64| Part 9| September 2008| Pages i55-i56

doi:10.1107/S1600536808023477

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Dicaesium hexamercury heptasulfide

Daniel E. Bugaris ^a and James A. Ibers ^a ^*

^aDepartment of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
^*Correspondence e-mail: ibers@chem.northwestern.edu

(Received 30 June 2008; accepted 24 July 2008; online 9 August 2008)

The title compound, Cs₂Hg₆S₇, crystallizes in a new structure type that is closely related to that of K₂Zn₆O₇. The structure comprises a three-dimensional mercury sulfide network that is composed of channels. These channels, which are along [001], are of two different diameters. The crystal structure contains one Cs, two Hg, and three S atoms in the asymmetric unit. The Cs, one Hg, and one S atom are at sites of symmetry m, whereas a second S atom is at a site of symmetry 2mm. The Hg atoms are bound to the S atoms in both three- and four-coordinate geometries. The caesium cations occupy the central spaces of the larger diameter channels and exhibit a coordination number of 7.

Related literature

For literature on related alkali-metal mercury sulfides, see: Sommer & Hoppe (1978 ) for A₆HgS₄ (A = K, Rb); Klepp & Prager (1992 ) for A₂HgS₂ (A = Na, K); Klepp (1992 ) for Na₂Hg₃S₄; Kanatzidis & Park (1990 ) for K₂Hg₃S₄ and K₂Hg₆S₇. For literature on other compounds with Hg—S or Cs—S bonds, see: Gulay et al. (2002 ); Rad & Hoppe (1981 ); Iwasaki (1973 ); Kinoshita et al. (1985 ); Bronger & Hendriks (1980 ). The isoformular, but not isotypic, compound K₂Zn₆O₇ was reported by Wambach & Hoppe (1978 ). For synthetic details, see: Sunshine et al. (1987 ). For computational details, see: Brown & Altermatt (1985 ); Gelato & Parthé (1987 ); Le Page (1988 ); Brese & O'Keeffe (1991 ); Spek (2003 ).

Experimental

Crystal data

Cs₂Hg₆S₇
M_r = 1693.78
Tetragonal, P 4₂ n m
a = 14.063 (3) Å
c = 4.1895 (18) Å
V = 828.6 (4) Å³
Z = 2
Mo Kα radiation
μ = 60.56 mm⁻¹
T = 215 (2) K
0.44 × 0.06 × 0.04 mm

Data collection

Bruker SMART 1000 CCD diffractometer
Absorption correction: face-indexed, numerical (SADABS; Sheldrick, 2006 ) T_min = 0.011, T_max = 0.131
8644 measured reflections
956 independent reflections
907 reflections with I > 2σ(I)
R_int = 0.052

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.082
S = 1.23
956 reflections
43 parameters
1 restraint
.
Δρ_max = 2.17 e Å⁻³
Δρ_min = −2.29 e Å⁻³
Absolute structure: Flack (1983 ), 389 Friedel pairs
Flack parameter: 0.00 (3)

Table 1
Selected geometric parameters (Å, °)

Hg1—S1	2.488 (4)
Hg1—S1ⁱ	2.540 (5)
Hg1—S1ⁱⁱ	2.549 (5)
Hg1—S3ⁱⁱⁱ	2.7754 (15)
Hg2—S3	2.367 (7)
Hg2—S2	2.377 (5)
Hg2—S3^iv	3.004 (7)
Cs1—S1^v	3.526 (5)
Cs1—S1ⁱⁱ	3.526 (5)
Cs1—S1^vi	3.561 (5)
Cs1—S1ⁱ	3.561 (5)
Cs1—S2^vii	3.566 (4)
Cs1—S3^iv	3.609 (7)
Cs1—S3	3.627 (7)

S1—Hg1—S1ⁱ	121.0 (2)
S1—Hg1—S1ⁱⁱ	120.6 (2)
S1ⁱ—Hg1—S1ⁱⁱ	110.83 (15)
S1—Hg1—S3ⁱⁱⁱ	104.78 (15)
S1ⁱ—Hg1—S3ⁱⁱⁱ	96.43 (18)
S1ⁱⁱ—Hg1—S3ⁱⁱⁱ	95.74 (17)
S3—Hg2—S2	168.5 (3)
S3—Hg2—S3^iv	101.9 (2)
S2—Hg2—S3^iv	89.7 (2)
Symmetry codes: (i) $[y-{\script{1\over 2}}, -x+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (ii) $[y-{\script{1\over 2}}, -x+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iii) $[-y+{\script{1\over 2}}, x+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iv) x, y, z-1; (v) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (vi) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (vii) $[-y+{\script{1\over 2}}, x+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2003 ); cell refinement: APEX2 (Bruker, 2006 ); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2008 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808023477/wm2184sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808023477/wm2184Isup2.hkl

checkCIF report

Comment top

Four structure types are found in alkali metal-mercury-sulfur ternary systems: A₆HgS₄ (A = K, Rb) exhibit discrete HgS₄ tetrahedra with intercalated alkali-metal cations (Sommer & Hoppe, 1978). A₂HgS₂ (A = Na, K) possess nearly linear HgS₂ units with alkali-metal cations occupying the voids (Klepp & Prager, 1992). The compounds Na₂Hg₃S₄ (Klepp, 1992) and K₂Hg₃S₄ (Kanatzidis & Park, 1990) feature infinite [Hg₃S₄]^2- units parallel to (100) separated by alkali-metal cations. K₂Hg₆S₇ has a three-dimensional mercury sulfide network composed of two types of channels, with the potassium cations occupying the spaces in the larger-diameter channels (Kanatzidis & Park, 1990).

Fig. 1 shows the unit cell of Cs₂Hg₆S₇. Similar to K₂Hg₆S₇, there is a three-dimensional mercury sulfide network containing two types of channels along [001]. There are two types of coordination geometries for the mercury atoms: Hg1 is four-coordinate with a distorted tetrahedral geometry and Hg2 is three-coordinate with a T-shaped planar geometry. The Hg1—S bond distances of 2.488 (4)-2.775 (2) Å are comparable to those of 2.345 (8)-2.718 (4) Å in K₂Hg₆S₇. The Hg2—S bond distances are 2.367 (7), 2.377 (5), and 3.004 (7) Å. In K₂Hg₆S₇, the Hg2 atom is considered to have a two-coordinate, nearly linear geometry. The Hg2 atom in Cs₂Hg₆S₇ can also be viewed as having an approximately linear bonding environment if the Hg2—S coordination distance of 3.004 (7) Å is considered to be non-bonding. However, there are some examples in the literature of longer than expected Hg—S bonds in extended solid-state structures, including 2.92 (1) Å in Hg₄SiS₆ (Gulay et al., 2002), and 2.98 (1) Å in BaHgS₂ (Rad & Hoppe, 1981). Long Hg—S bond distances of greater than 2.9 Å are more common in coordination compounds, including 2.965 (4) Å in Hg(S₂CNEt₂)₂ (Iwasaki, 1973), 3.137 (6) Å in Hg₂(S₂CNEt₂)₄ (Iwasaki, 1973), and 2.991 (3) Å and 3.322 (4) Å in [CoHg(SCN)₄{P(C₆H₅)₃}₂]₂ (Kinoshita et al., 1985). Therefore, we consider the Hg2 atom in Cs₂Hg₆S₇ to be three-coordinate with a T-shaped planar geometry. The Cs1 atoms, found in the centers of the larger-diameter channels, are seven-coordinate, with Cs—S distances of 3.526 (5)-3.627 (7) Å, as compared to 3.595 (7)-3.701 (6) Å in Cs₂Zn₃S₄ (Bronger & Hendriks, 1980).

Because there is no S—S bonding in Cs₂Hg₆S₇, a formal oxidation state of -II can be assigned to the S atoms. Bond valence sums (Brown & Altermatt, 1985; Brese & O'Keeffe, 1991) of Hg1 = 1.95, Hg2 = 1.84, and Cs1 = 1.13 confirm the formal oxidation states of +II for both Hg atoms, and +I for Cs.

Although they possess structural similarities, Cs₂Hg₆S₇ and K₂Hg₆S₇ are not isostructural. Cs₂Hg₆S₇ belongs to space group P4₂nm and K₂Hg₆S₇ belongs to space group P42₁m. Another related compound is K₂Zn₆O₇, which crystallizes in space group P4₂nm (Wambach & Hoppe, 1978). However, the ADDSYM algorithm (Le Page, 1988) in PLATON (Spek, 2003) suggests that K₂Zn₆O₇ properly belongs to space group P4₂/mnm. Apparently, Cs₂Hg₆S₇ is not isostructural to K₂Zn₆O₇ and instead crystallizes in a new structure type.

Related literature top

For literature on related alkali metal mercury sulfides, see: Sommer & Hoppe (1978) for A₆HgS₄ (A = K, Rb); Klepp & Prager (1992) for A₂HgS₂ (A = Na, K); Klepp (1992) for Na₂Hg₃S₄; Kanatzidis & Park (1990) for K₂Hg₃S₄ and K₂Hg₆S₇. For literature on other compounds with Hg—S or Cs—S bonds, see: Gulay et al. (2002); Rad & Hoppe (1981); Iwasaki (1973); Kinoshita et al. (1985); Bronger & Hendriks (1980). The isoformular, but not isotypic, compound K₂Zn₆O₇ was reported by Wambach & Hoppe (1978). For synthetic details, see: Sunshine et al. (1987). For computational details, see: Brown & Altermatt (1985); Gelato & Parthé (1987); Le Page (1988); Brese & O'Keeffe (1991); Spek (2003).

Experimental top

Cs₂Hg₆S₇ was initially obtained in an attempt to produce a Cs/Hg/U/S quaternary phase. Cs₂Hg₆S₇ was then synthesized rationally from a solid-state reaction of Cs₂S₃ (0.13 mmol), HgS (Alfa Aesar, 0.21 mmol), and S (Mallinckrodt, 99.6%, 0.44 mmol). CsI (Aldrich, 99.9%, 0.34 mmol) was added to aid in the crystallization of the final product. The Cs₂S₃ reactive flux (Sunshine et al., 1987) was prepared by the stoichiometric reaction of Cs (Strem Chemicals, 99.5%) and S in liquid NH₃ at 194 K. The reactants were loaded into a fused-silica tube under an Ar atmosphere in a glove box. The tube was evacuated to 10 ^-4 Torr, sealed, and then placed in a computer-controlled furnace. The sample was heated to 1123 K in 24 hours, kept at 1123 K for 120 h, cooled at 5 K h^-1 to 473 K, and then cooled to 293 K in 2 hours. The resulting black needles were washed with N,N-dimethylformamide. The yield was about 80% based on Hg.

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: APEX2 (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

Fig. 1. A view down [001] of the unit cell of Cs₂Hg₆S₇, with displacement ellipsoids at the 95% probability level.

Dicaesium hexamercury heptasulfide top

Crystal data top

Cs₂Hg₆S₇	D_x = 6.789 Mg m⁻³
M_r = 1693.78	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4₂nm	Cell parameters from 5893 reflections
Hall symbol: P 4n -2n	θ = 2.9–28.1°
a = 14.063 (3) Å	µ = 60.56 mm⁻¹
c = 4.1895 (18) Å	T = 215 K
V = 828.6 (4) Å³	Needle, black
Z = 2	0.44 × 0.06 × 0.04 mm
F(000) = 1404

Data collection top

Bruker SMART 1000 CCD diffractometer	956 independent reflections
Radiation source: fine-focus sealed tube	907 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.052
ω scans	θ_max = 28.1°, θ_min = 2.1°
Absorption correction: numerical (SADABS; Sheldrick, 2006)	h = −17→17
T_min = 0.011, T_max = 0.131	k = −17→17
8644 measured reflections	l = −5→5

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0235P)² + 40.9819P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.034	(Δ/σ)_max < 0.001
wR(F²) = 0.082	Δρ_max = 2.17 e Å⁻³
S = 1.23	Δρ_min = −2.29 e Å⁻³
956 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
43 parameters	Extinction coefficient: 0.00320 (17)
1 restraint	Absolute structure: Flack (1983), 389 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.00 (3)

Crystal data top

Cs₂Hg₆S₇	Z = 2
M_r = 1693.78	Mo Kα radiation
Tetragonal, P4₂nm	µ = 60.56 mm⁻¹
a = 14.063 (3) Å	T = 215 K
c = 4.1895 (18) Å	0.44 × 0.06 × 0.04 mm
V = 828.6 (4) Å³

Data collection top

Bruker SMART 1000 CCD diffractometer	956 independent reflections
Absorption correction: numerical (SADABS; Sheldrick, 2006)	907 reflections with I > 2σ(I)
T_min = 0.011, T_max = 0.131	R_int = 0.052
8644 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.034	w = 1/[σ²(F_o²) + (0.0235P)² + 40.9819P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.082	Δρ_max = 2.17 e Å⁻³
S = 1.23	Δρ_min = −2.29 e Å⁻³
956 reflections	Absolute structure: Flack (1983), 389 Friedel pairs
43 parameters	Absolute structure parameter: 0.00 (3)
1 restraint

Special details top

Experimental. The absorption correction program used the face indices and crystal dimensions that were supplied.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Hg1	0.15251 (5)	0.57410 (5)	0.22339 (19)	0.0216 (2)
Hg2	0.09922 (5)	0.09922 (5)	0.3162 (3)	0.0189 (3)
Cs1	0.33108 (8)	0.33108 (8)	0.2149 (5)	0.0197 (3)
S1	0.0207 (3)	0.6920 (3)	0.2220 (13)	0.0151 (7)
S2	0.0000	0.0000	0.000 (2)	0.0193 (19)
S3	0.1828 (3)	0.1828 (3)	0.7187 (18)	0.0153 (11)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Hg1	0.0248 (4)	0.0215 (4)	0.0184 (4)	0.0052 (3)	0.0002 (3)	−0.0002 (3)
Hg2	0.0180 (3)	0.0180 (3)	0.0206 (5)	−0.0015 (4)	−0.0032 (3)	−0.0032 (3)
Cs1	0.0216 (5)	0.0216 (5)	0.0157 (7)	0.0037 (5)	−0.0013 (6)	−0.0013 (6)
S1	0.0134 (18)	0.0160 (18)	0.0158 (18)	−0.0006 (14)	−0.0002 (19)	−0.0017 (19)
S2	0.024 (3)	0.024 (3)	0.011 (4)	−0.006 (4)	0.000	0.000
S3	0.0154 (15)	0.0154 (15)	0.015 (2)	0.002 (2)	−0.003 (2)	−0.003 (2)

Geometric parameters (Å, º) top

Hg1—S1	2.488 (4)	Cs1—S2^iv	3.566 (4)
Hg1—S1ⁱ	2.540 (5)	Cs1—S3^v	3.609 (7)
Hg1—S1ⁱⁱ	2.549 (5)	Cs1—S3	3.627 (7)
Hg1—S3ⁱⁱⁱ	2.7754 (15)	Cs1—Hg1^viii	4.1659 (17)
Hg1—Cs1^iv	4.1659 (17)	Cs1—Hg1ⁱⁱ	4.1659 (17)
Hg1—Cs1ⁱⁱⁱ	4.2013 (18)	Cs1—Cs1^x	4.1895 (18)
Hg1—Cs1	4.2412 (12)	Cs1—Cs1^v	4.1895 (18)
Hg2—S3	2.367 (7)	Cs1—Hg1ⁱ	4.2013 (18)
Hg2—S2	2.377 (5)	S1—Hg1ⁱⁱⁱ	2.540 (5)
Hg2—S3^v	3.004 (7)	S1—Hg1^iv	2.549 (5)
Hg2—Cs1ⁱ	4.2392 (19)	S1—Cs1^iv	3.526 (5)
Hg2—Cs1^vi	4.2392 (18)	S1—Cs1ⁱⁱⁱ	3.561 (5)
Hg2—Cs1	4.631 (2)	S2—Hg2^xi	2.377 (5)
Hg2—Cs1ⁱⁱ	4.640 (2)	S2—Cs1ⁱⁱ	3.566 (4)
Hg2—Cs1^vii	4.640 (2)	S2—Cs1^vii	3.566 (4)
Cs1—S1^viii	3.526 (5)	S3—Hg1^ix	2.7754 (14)
Cs1—S1ⁱⁱ	3.526 (5)	S3—Hg1ⁱ	2.7754 (14)
Cs1—S1^ix	3.561 (5)	S3—Hg2^x	3.004 (7)
Cs1—S1ⁱ	3.561 (5)	S3—Cs1^x	3.609 (7)

S1—Hg1—S1ⁱ	121.0 (2)	S1^ix—Cs1—S2^iv	77.06 (11)
S1—Hg1—S1ⁱⁱ	120.6 (2)	S1ⁱ—Cs1—S2^iv	77.06 (11)
S1ⁱ—Hg1—S1ⁱⁱ	110.83 (15)	S1^viii—Cs1—S3^v	71.57 (10)
S1—Hg1—S3ⁱⁱⁱ	104.78 (15)	S1ⁱⁱ—Cs1—S3^v	71.57 (10)
S1ⁱ—Hg1—S3ⁱⁱⁱ	96.43 (18)	S1^ix—Cs1—S3^v	111.39 (9)
S1ⁱⁱ—Hg1—S3ⁱⁱⁱ	95.74 (17)	S1ⁱ—Cs1—S3^v	111.39 (9)
S1—Hg1—Cs1^iv	57.59 (10)	S2^iv—Cs1—S3^v	164.39 (19)
S1ⁱ—Hg1—Cs1^iv	92.09 (11)	S1^viii—Cs1—S3	111.21 (9)
S1ⁱⁱ—Hg1—Cs1^iv	148.09 (10)	S1ⁱⁱ—Cs1—S3	111.21 (9)
S3ⁱⁱⁱ—Hg1—Cs1^iv	58.64 (13)	S1^ix—Cs1—S3	70.96 (10)
S1—Hg1—Cs1ⁱⁱⁱ	57.74 (11)	S1ⁱ—Cs1—S3	70.96 (10)
S1ⁱ—Hg1—Cs1ⁱⁱⁱ	148.92 (10)	S2^iv—Cs1—S3	124.85 (19)
S1ⁱⁱ—Hg1—Cs1ⁱⁱⁱ	91.15 (11)	S3^v—Cs1—S3	70.76 (11)
S3ⁱⁱⁱ—Hg1—Cs1ⁱⁱⁱ	58.46 (14)	Hg1^viii—Cs1—Hg1ⁱⁱ	81.48 (4)
Cs1^iv—Hg1—Cs1ⁱⁱⁱ	60.09 (3)	S1^viii—Cs1—Hg1ⁱ	146.72 (8)
S1—Hg1—Cs1	168.11 (10)	S1ⁱⁱ—Cs1—Hg1ⁱ	77.73 (8)
S1ⁱ—Hg1—Cs1	56.93 (10)	S1^ix—Cs1—Hg1ⁱ	103.37 (9)
S1ⁱⁱ—Hg1—Cs1	56.13 (10)	S1ⁱ—Cs1—Hg1ⁱ	36.20 (6)
S3ⁱⁱⁱ—Hg1—Cs1	87.09 (12)	S2^iv—Cs1—Hg1ⁱ	111.51 (11)
Cs1^iv—Hg1—Cs1	132.09 (4)	S3^v—Cs1—Hg1ⁱ	80.02 (9)
Cs1ⁱⁱⁱ—Hg1—Cs1	131.02 (4)	S3—Cs1—Hg1ⁱ	40.70 (2)
S3—Hg2—S2	168.5 (3)	Hg1^viii—Cs1—Hg1ⁱ	110.24 (4)
S3—Hg2—S3^v	101.9 (2)	Hg1ⁱⁱ—Cs1—Hg1ⁱ	60.09 (3)
S2—Hg2—S3^v	89.7 (2)	Cs1^x—Cs1—Hg1ⁱ	59.53 (3)
S3—Hg2—Cs1ⁱ	92.64 (11)	Cs1^v—Cs1—Hg1ⁱ	120.47 (3)
S2—Hg2—Cs1ⁱ	80.40 (11)	Hg1—S1—Hg1ⁱⁱⁱ	104.31 (17)
S3^v—Hg2—Cs1ⁱ	125.85 (4)	Hg1—S1—Hg1^iv	104.03 (17)
S3—Hg2—Cs1^vi	92.64 (11)	Hg1ⁱⁱⁱ—S1—Hg1^iv	110.83 (15)
S2—Hg2—Cs1^vi	80.40 (11)	Hg1—S1—Cs1^iv	85.86 (12)
S3^v—Hg2—Cs1^vi	125.85 (4)	Hg1ⁱⁱⁱ—S1—Cs1^iv	155.98 (17)
Cs1ⁱ—Hg2—Cs1^vi	104.84 (5)	Hg1^iv—S1—Cs1^iv	86.99 (14)
S3—Hg2—Cs1	50.68 (17)	Hg1—S1—Cs1ⁱⁱⁱ	86.05 (12)
S2—Hg2—Cs1	140.87 (19)	Hg1ⁱⁱⁱ—S1—Cs1ⁱⁱⁱ	86.37 (14)
S3^v—Hg2—Cs1	51.17 (12)	Hg1^iv—S1—Cs1ⁱⁱⁱ	156.55 (16)
Cs1ⁱ—Hg2—Cs1	119.97 (2)	Cs1^iv—S1—Cs1ⁱⁱⁱ	72.47 (8)
Cs1^vi—Hg2—Cs1	119.97 (2)	Hg2—S2—Hg2^xi	112.2 (4)
S3—Hg2—Cs1ⁱⁱ	133.26 (3)	Hg2—S2—Cs1ⁱⁱ	100.76 (3)
S2—Hg2—Cs1ⁱⁱ	49.02 (6)	Hg2^xi—S2—Cs1ⁱⁱ	100.76 (3)
S3^v—Hg2—Cs1ⁱⁱ	77.46 (8)	Hg2—S2—Cs1^vii	100.76 (3)
Cs1ⁱ—Hg2—Cs1ⁱⁱ	56.09 (3)	Hg2^xi—S2—Cs1^vii	100.76 (3)
Cs1^vi—Hg2—Cs1ⁱⁱ	126.15 (3)	Cs1ⁱⁱ—S2—Cs1^vii	140.9 (3)
Cs1—Hg2—Cs1ⁱⁱ	111.95 (3)	Hg2—S3—Hg1^ix	98.40 (15)
S3—Hg2—Cs1^vii	133.26 (3)	Hg2—S3—Hg1ⁱ	98.40 (15)
S2—Hg2—Cs1^vii	49.02 (6)	Hg1^ix—S3—Hg1ⁱ	156.8 (2)
S3^v—Hg2—Cs1^vii	77.46 (8)	Hg2—S3—Hg2^x	101.9 (2)
Cs1ⁱ—Hg2—Cs1^vii	126.15 (3)	Hg1^ix—S3—Hg2^x	96.04 (16)
Cs1^vi—Hg2—Cs1^vii	56.09 (3)	Hg1ⁱ—S3—Hg2^x	96.04 (16)
Cs1—Hg2—Cs1^vii	111.95 (3)	Hg2—S3—Cs1^x	169.7 (3)
Cs1ⁱⁱ—Hg2—Cs1^vii	92.79 (5)	Hg1^ix—S3—Cs1^x	80.31 (13)
S1^viii—Cs1—S1ⁱⁱ	108.22 (17)	Hg1ⁱ—S3—Cs1^x	80.31 (13)
S1^viii—Cs1—S1^ix	72.47 (8)	Hg2^x—S3—Cs1^x	88.40 (19)
S1ⁱⁱ—Cs1—S1^ix	176.94 (13)	Hg2—S3—Cs1	99.0 (2)
S1^viii—Cs1—S1ⁱ	176.94 (13)	Hg1^ix—S3—Cs1	80.83 (13)
S1ⁱⁱ—Cs1—S1ⁱ	72.47 (8)	Hg1ⁱ—S3—Cs1	80.83 (13)
S1^ix—Cs1—S1ⁱ	106.68 (16)	Hg2^x—S3—Cs1	159.2 (2)
S1^viii—Cs1—S2^iv	99.89 (11)	Cs1^x—S3—Cs1	70.76 (11)
S1ⁱⁱ—Cs1—S2^iv	99.89 (11)

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

Experimental details

Crystal data
Chemical formula	Cs₂Hg₆S₇
M_r	1693.78
Crystal system, space group	Tetragonal, P4₂nm
Temperature (K)	215
a, c (Å)	14.063 (3), 4.1895 (18)
V (Å³)	828.6 (4)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	60.56
Crystal size (mm)	0.44 × 0.06 × 0.04

Data collection
Diffractometer	Bruker SMART 1000 CCD diffractometer
Absorption correction	Numerical (SADABS; Sheldrick, 2006)
T_min, T_max	0.011, 0.131
No. of measured, independent and observed [I > 2σ(I)] reflections	8644, 956, 907
R_int	0.052
(sin θ/λ)_max (Å⁻¹)	0.664

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.082, 1.23
No. of reflections	956
No. of parameters	43
No. of restraints	1
	w = 1/[σ²(F_o²) + (0.0235P)² + 40.9819P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	2.17, −2.29
Absolute structure	Flack (1983), 389 Friedel pairs
Absolute structure parameter	0.00 (3)

Computer programs: SMART (Bruker, 2003), APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), CrystalMaker (Palmer, 2008).

Selected geometric parameters (Å, º) top

Hg1—S1	2.488 (4)	Cs1—S1^v	3.526 (5)
Hg1—S1ⁱ	2.540 (5)	Cs1—S1ⁱⁱ	3.526 (5)
Hg1—S1ⁱⁱ	2.549 (5)	Cs1—S1^vi	3.561 (5)
Hg1—S3ⁱⁱⁱ	2.7754 (15)	Cs1—S1ⁱ	3.561 (5)
Hg2—S3	2.367 (7)	Cs1—S2^vii	3.566 (4)
Hg2—S2	2.377 (5)	Cs1—S3^iv	3.609 (7)
Hg2—S3^iv	3.004 (7)	Cs1—S3	3.627 (7)

S1—Hg1—S1ⁱ	121.0 (2)	S1ⁱⁱ—Hg1—S3ⁱⁱⁱ	95.74 (17)
S1—Hg1—S1ⁱⁱ	120.6 (2)	S3—Hg2—S2	168.5 (3)
S1ⁱ—Hg1—S1ⁱⁱ	110.83 (15)	S3—Hg2—S3^iv	101.9 (2)
S1—Hg1—S3ⁱⁱⁱ	104.78 (15)	S2—Hg2—S3^iv	89.7 (2)
S1ⁱ—Hg1—S3ⁱⁱⁱ	96.43 (18)

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

Acknowledgements

This research was supported by the US Department of Energy, Basic Energy Sciences Grant ER-15522.

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