K₂[O(HgSO₃)₃], a new sulfito­mercurate with an [OHg₃] core

The structure of dipotassium μ₃-oxido-tris[sulfitomercur­ate(II)], K₂[O(HgSO₃)₃], is characterized by segregation of the K⁺ cations and complex [O(HgSO₃)₃]²⁻ anions into layers parallel to (010). The anion has m symmetry and is a new example of a μ₃-oxido-trimercurate complex with a central [OHg₃] core. This unit adopts the shape of a flat, almost trigonal, pyramid (mean O—Hg = 2.072 Å and mean Hg—O—Hg = 110.8°). The two independent Hg—S bonds have nearly the same length (mean Hg—S = 2.335 Å). Due to inter­molecular O...Hg donor–acceptor inter­actions greater than 2.65 Å, the O—Hg—S fragments are slightly bent. The [KO₉] coordination polyhedron of the K⁺ cation approaches a distorted tricapped trigonal prism with a [6+1+2] coordination.

S1. Comment

In a recent project we have studied the formation conditions and crystal structures of (NH₄)[Hg(SO₃)Cl] and (NH₄)₂[Hg(SO₃)₂] (Weil et al., 2007). Continuing our work on sulfite complexes of mercury, we have also investigated in some detail the systems K₂SO₃–HgX₂ (X = Cl or Br) in aqueous solutions and the solid phases formed therein. Depending on the molar ratios of the components and on the conditions, several phases with the general formula xK[XHgSO₃].yHgX₂.zKX were obtained. A characteristic of all phases structurally studied so far is the segregation of the K⁺ cations and of the anions and HgX₂ molecules into layers (Weil et al., 2008). On heating solid HgO in an aqueous K₂SO₃ solution, a related phase was obtained, viz. a formally basic salt of composition K₂SO₃·2HgSO₃·HgO, or, with respect to the crystal structure determination presented here, K₂[O(HgSO₃)₃].

The asymmetric unit of the title compound contains one K, two Hg, two S and six O sites. As in the above-mentioned xK[XHgSO₃].yHgX₂.zKX structures, a segregation of cations (K⁺) and anions {[O(HgSO₃)₃]^2-} into layers is a characteristic feature of the structure, here with a stacking of the layers parallel to (010) (Fig. 1). The cationic and anionic layers adopt the symmetries (a:c).2₁:α-p112₁/a and (a:c).m.2₁-p2₁ma, respectively (Shubnikov & Koptsik, 1974). The [O(HgSO₃)₃]^2- complex anion has site symmetry m, with the mirror plane running through atoms O5/Hg2/S2/O6 (Fig. 2). The anion is related to the [O(HgCl)₃]⁺ and [O(HgI)₂(HgOH)]⁺ cationic complexes which are present in the structures of 2HgCl₂·HgO {or, in a more detailed formula, [O(HgCl)₃]Cl} (Aurivillius, 1964) and [O(HgI)₂(HgOH)]ClO₄ (Köhler et al., 1974, 1975). Both the anionic and the two cationic complexes contain flat nearly trigonal–pyramidal [OHg₃] cores, i.e. they are all trimercurio–oxonium complexes which are representatives of metallo complexes, and thus they exhibit similar bonding parameters. In the anionic complex, the average O—Hg bond length is 2.07 Å (Table 1), compared with 2.04 and 2.05 Å, respectively, in the cationic complexes. The slight difference may be due to the strong trans-influence of the sulfite ligands and to the different charges, which is also mirrored in the different average Hg—O—Hg bond angles of 110.8° for the anionic complex and of 118.9 and 119.8° for the cationic complexes.

In the title compound, the average Hg—S bond length is 2.335 Å (Table 1), and the O—Hg—S structural fragments are slightly bent with only a minor deviation from linearity (mean O—Hg—S angle = 174.7°), due to the intermolecular donor–acceptor interactions with S—O····Hg > 2.65 Å. These interactions cause linking of the anions to the above-mentioned layers and the remote O atoms expand the coordination spheres of the Hg²⁺ cations to five- and six-coordination if Hg—O distances > 3.0 Å are neglected. The average Hg—S bond length is similar to the average Hg—Cl distance of 2.31 Å in [O(HgCl)₃]Cl and in good agreement with the Hg—S bond lengths in the sulfitomercurates (NH₄)[Hg(SO₃)Cl], (NH₄)₂[Hg(SO₃)₂] (Weil et al., 2007) and Na₂[Hg(SO₃)₂]·H₂O (Nyberg & Cynkier, 1972), with average values of 2.394, 2.364 and 2.406 Å, respectively. In contrast with K₂[O(HgSO₃)₃], in the latter structures Cl—Hg—SO₃ and O₃S—Hg—SO₃ moieties are present. Nevertheless, in agreement with the preference of mercury for linear coordination, the Cl—Hg—S and S—Hg—S angles are close to 180 °, viz. 165.5, 174.4 and 172.8 °, respectively.

The S—O bond lengths of the two independent SO₃ groups in K₂[O(HgSO₃)₃] differ slightly (mean S—O = 1.460 and 1.473 Å) because of their different roles in the linking within and between the cationic and anionic layers. Not all of the O atoms of the SO₃ groups are involved in donor–acceptor interactions within the anionic layers, and only some of the O atoms are coordinated to the K⁺ cation, and thus contribute to the linking of the cationic and anionic layers. The K⁺ cation has nine O neighbours with a [6 + 1+2] coordination and with K—O distances ranging from 2.801 (4) to 3.276 (5) Å (Table 1). The resulting coordination polyhedron may be described as a distorted tricapped trigonal prism.

Results from bond-valence sum calculations (Brown, 2002), using the parameters of Brese & O'Keeffe (1991), are in good agreement with the expected values for K, Hg and O (expected 1, 2 and 2): Hg1, Hg2 (including all distances < 3.0 Å) 1.99 and 2.10; K 1.07; O1 [coordination number (CN) = 5; 1 S, 2 Hg, 2 K] 1.94, O2 (CN = 4; 1 S, 3 K) 1.97, O3 (CN = 4; 1 S, 3 K) 2.11, O4 (CN = 4; 1 S, 1 Hg, 2 K) 1.90, O5 (CN = 3; 3 Hg) 2.29 and O6 (CN = 4; 1 S, 3 Hg) 2.04. Following this concept, the S atoms are considerably `overbonded', with valence units of 5.87 for S1 and 5.75 for S2. This behaviour is attributed to the additional metal–sulfur coordination via the lone-pair electrons of the S atoms, which leads to enhanced S—O π-bonding as a consequence (Cruickshank, 1961), and thus to shorter S—O bond lengths. So, in comparison with other sulfates(IV) of the formula type MS^IVO₃ (M is a divalent metal) where the S atom is not coordinated to the metal centres, the overall S—O distance is significantly shorter here (1.47 versus 1.54 Å). Nevertheless, the bonding situation in the title compound is in agreement with the HSAB (hard and soft acids and bases) concept, where the soft acid Hg²⁺ prefers bonding to the soft base S^IV with its lone-pair electrons.

Related literature

For related literature, see: Aurivillius (1964); Brese & O'Keeffe (1991); Brown (2002); Cruickshank (1961); Gelato & Parthé (1987); Köhler et al. (1974, 1975); Nyberg & Cynkier (1972); Shubnikov & Koptsik (1974); Weil et al. (2007, 2008).

S2. Experimental

All chemicals used were of analytical grade (Merck) and employed without further purification. The title compound was obtained on dissolution of freshly precipitated HgO (25 mg, 0.115 mmol) in a boiling aqueous solution of K₂SO₃ (50 ml, 180 mg, 1.1 mmol). After cooling to ambient temperature, aggregated yellowish crystals with a lancet-like habit and of up to 2 mm in length were formed within 2 d. The crystals were not stable over a long period and decomposed within a few days under formation of elemental mercury and SO₂. However, when the crystals were embedded in perfluorinated ether, collection of a complete data set with high redundancy was possible without difficulty.

S3. Refinement

Structure data were standardized using STRUCTURETIDY (Gelato & Parthé, 1987). The highest remaining peak in the final difference Fourier map is 0.76 Å from atom Hg2 and the deepest hole is 0.90 Å from atom Hg1.

Computing details

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

Figures

	Fig. 1. The crystal structure of K2[O(HgSO3)3] in projection along [100], showing the layered character of the cationic and anionic moieties.
	Fig. 2. The [O(HgSO3)3]^2- anion with the atom-labelling scheme. Displacement ellipsoids are drawn at the 90% probability level. [Symmetry codes: (i) x - 1/2, -y + 1/2, -z + 1/2; (ii) x - 1/2, y, -z + 1/2; (iii) -x + 1/2, -y + 1/2, z + 1/2; (iv) -x + 1/2, y - 1/2, z + 1/2; (v) x + 1/2, -y + 1/2, -z + 3/2; (vi) x + 1/2, y, -z + 3/2; (vii) x, -y + 1/2, z + 1; (viii) x, y, z + 1.]

dipotassium µ₃-oxido-tris[sulfitomercury(II)]

Crystal data

K2[O(HgSO3)3]	F(000) = 1624
Mr = 936.15	Dx = 5.243 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 4956 reflections
a = 7.352 (4) Å	θ = 2.8–30.0°
b = 20.734 (11) Å	µ = 40.01 mm^−1
c = 7.780 (4) Å	T = 298 K
V = 1185.9 (11) Å^3	Plate, light yellow
Z = 4	0.12 × 0.11 × 0.04 mm

Data collection

Bruke SMART APEX CCD area-detector diffractometer	1763 independent reflections
Radiation source: fine-focus sealed tube	1612 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.046
ω scans	θmax = 30.0°, θmin = 2.8°
Absorption correction: numerical (HABITUS; Herrendorf, 1997)	h = −10→10
Tmin = 0.086, Tmax = 0.327	k = −28→25
12066 measured reflections	l = −10→10

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.023	Secondary atom site location: difference Fourier map
wR(F^2) = 0.055	w = 1/[σ^2(Fo^2) + (0.0284P)^2 + 1.2995P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.002
1763 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
89 parameters	Extinction coefficient: 0.00048 (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
Hg1	0.22565 (3)	0.170861 (10)	0.76734 (3)	0.01824 (8)
Hg2	0.05090 (3)	0.2500	0.41045 (3)	0.01651 (9)
K	−0.13687 (15)	0.05982 (6)	0.13114 (18)	0.0265 (3)
S1	0.36893 (15)	0.08535 (6)	0.90930 (16)	0.0168 (2)
S2	0.0100 (2)	0.2500	0.1142 (2)	0.0141 (3)
O1	0.5250 (5)	0.1127 (2)	1.0028 (6)	0.0271 (9)
O2	0.4237 (6)	0.0389 (2)	0.7793 (6)	0.0331 (10)
O3	0.2341 (5)	0.0593 (2)	1.0274 (6)	0.0285 (9)
O4	−0.0900 (5)	0.1915 (2)	0.0636 (5)	0.0260 (8)
O5	0.0828 (6)	0.2500	0.6721 (6)	0.0157 (9)
O6	0.1939 (7)	0.2500	0.0394 (6)	0.0260 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.02221 (11)	0.01385 (12)	0.01866 (12)	0.00044 (6)	−0.00345 (7)	0.00189 (7)
Hg2	0.01677 (12)	0.02136 (15)	0.01138 (14)	0.000	−0.00022 (8)	0.000
K	0.0250 (5)	0.0191 (6)	0.0355 (7)	0.0009 (4)	0.0020 (5)	0.0037 (5)
S1	0.0179 (5)	0.0125 (6)	0.0200 (6)	0.0001 (4)	−0.0002 (4)	0.0015 (5)
S2	0.0137 (6)	0.0163 (8)	0.0125 (7)	0.000	−0.0007 (6)	0.000
O1	0.0254 (17)	0.021 (2)	0.035 (2)	−0.0024 (15)	−0.0121 (16)	0.0002 (19)
O2	0.036 (2)	0.024 (2)	0.039 (3)	0.0090 (19)	0.0039 (18)	−0.009 (2)
O3	0.0230 (17)	0.034 (2)	0.029 (2)	−0.0062 (15)	0.0020 (15)	0.0122 (19)
O4	0.0320 (19)	0.019 (2)	0.027 (2)	−0.0062 (16)	−0.0086 (16)	−0.0024 (17)
O5	0.025 (2)	0.011 (2)	0.011 (2)	0.000	−0.0010 (18)	0.000
O6	0.015 (2)	0.052 (4)	0.011 (2)	0.000	0.0027 (19)	0.000

Geometric parameters (Å, º)

Hg1—O5	2.084 (3)	K—O2^ix	3.021 (5)
Hg1—S1	2.3395 (15)	K—O2^iv	3.253 (5)
Hg1—O6^i	2.688 (4)	K—O1^ii	3.276 (5)
Hg1—O1^ii	2.837 (5)	K—S1^ix	3.474 (2)
Hg1—O4^iii	2.941 (4)	K—S1^ii	3.614 (3)
Hg1—O3	3.074 (4)	S1—O2	1.453 (4)
Hg2—O5	2.049 (5)	S1—O3	1.455 (4)
Hg2—S2	2.325 (2)	S1—O1	1.472 (4)
Hg2—O6^iv	2.654 (5)	S1—Hg1^xi	3.4512 (17)
Hg2—O4^v	2.913 (4)	S2—O6	1.472 (5)
Hg2—O4^iii	2.913 (4)	S2—O4	1.473 (4)
Hg2—O1^vi	2.932 (5)	S2—O4^xii	1.473 (4)
K—O4	2.801 (4)	S2—Hg2^iv	3.381 (2)
K—O3^ii	2.821 (5)	S2—Hg1^xiii	3.533 (2)
K—O2^vii	2.824 (4)	S2—Hg1^viii	3.533 (2)
K—O3^viii	2.845 (4)	S2—Hg2^iii	3.981 (3)
K—O3^ix	2.852 (5)	S2—Hg1^iv	3.984 (2)
K—O1^x	2.895 (4)	S2—Hg1^xiv	3.984 (2)
O5—Hg1—S1	172.45 (14)	Hg1^xiii—S2—Hg2^iii	61.00 (3)
O5—Hg1—O6^i	75.84 (15)	Hg1^viii—S2—Hg2^iii	61.00 (3)
S1—Hg1—O6^i	97.48 (9)	O6—S2—Hg1^iv	100.8 (2)
O5—Hg1—O1^ii	79.00 (14)	O4—S2—Hg1^iv	36.83 (17)
S1—Hg1—O1^ii	105.18 (10)	O4^xii—S2—Hg1^iv	83.02 (17)
O6^i—Hg1—O1^ii	142.89 (13)	Hg2—S2—Hg1^iv	143.76 (5)
O5—Hg1—O4^iii	78.86 (16)	Hg2^iv—S2—Hg1^iv	55.52 (3)
S1—Hg1—O4^iii	108.41 (9)	Hg1^xiii—S2—Hg1^iv	81.83 (5)
O6^i—Hg1—O4^iii	129.84 (11)	Hg1^viii—S2—Hg1^iv	58.36 (4)
O1^ii—Hg1—O4^iii	69.68 (12)	Hg2^iii—S2—Hg1^iv	119.24 (4)
O5—Hg1—O3	146.78 (15)	O6—S2—Hg1^xiv	100.8 (2)
S1—Hg1—O3	27.10 (7)	O4—S2—Hg1^xiv	83.02 (17)
O6^i—Hg1—O3	86.73 (12)	O4^xii—S2—Hg1^xiv	36.83 (17)
O1^ii—Hg1—O3	100.28 (12)	Hg2—S2—Hg1^xiv	143.76 (5)
O4^iii—Hg1—O3	132.55 (12)	Hg2^iv—S2—Hg1^xiv	55.52 (3)
O5—Hg2—S2	179.14 (14)	Hg1^xiii—S2—Hg1^xiv	58.36 (4)
O5—Hg2—O6^iv	88.11 (17)	Hg1^viii—S2—Hg1^xiv	81.83 (5)
S2—Hg2—O6^iv	91.03 (12)	Hg2^iii—S2—Hg1^xiv	119.24 (4)
O5—Hg2—O4^v	80.07 (14)	Hg1^iv—S2—Hg1^xiv	48.64 (3)
S2—Hg2—O4^v	100.71 (9)	S1—O1—Hg1^xi	101.7 (2)
O6^iv—Hg2—O4^v	152.41 (9)	S1—O1—K^xv	133.9 (2)
O5—Hg2—O4^iii	80.07 (14)	Hg1^xi—O1—K^xv	88.27 (11)
S2—Hg2—O4^iii	100.71 (9)	S1—O1—Hg2^xi	122.6 (2)
O6^iv—Hg2—O4^iii	152.41 (9)	Hg1^xi—O1—Hg2^xi	73.99 (11)
O4^v—Hg2—O4^iii	49.26 (16)	K^xv—O1—Hg2^xi	103.45 (12)
O5—Hg2—O1^vi	77.21 (9)	S1—O1—Hg1	46.07 (13)
S2—Hg2—O1^vi	102.70 (9)	Hg1^xi—O1—Hg1	76.51 (11)
O6^iv—Hg2—O1^vi	84.37 (7)	K^xv—O1—Hg1	163.48 (17)
O4^v—Hg2—O1^vi	68.79 (11)	Hg2^xi—O1—Hg1	78.76 (10)
O4^iii—Hg2—O1^vi	116.59 (11)	S1—O1—K^xi	90.99 (19)
O4—K—O3^ii	102.80 (13)	Hg1^xi—O1—K^xi	167.26 (14)
O4—K—O2^vii	135.63 (13)	K^xv—O1—K^xi	83.41 (11)
O3^ii—K—O2^vii	78.43 (13)	Hg2^xi—O1—K^xi	98.54 (13)
O4—K—O3^viii	80.36 (13)	Hg1—O1—K^xi	112.65 (12)
O3^ii—K—O3^viii	126.13 (11)	S1—O2—K^xvi	156.6 (3)
O2^vii—K—O3^viii	65.23 (13)	S1—O2—K^ix	95.4 (2)
O4—K—O3^ix	142.54 (13)	K^xvi—O2—K^ix	89.43 (14)
O3^ii—K—O3^ix	108.64 (10)	S1—O2—Hg1	46.08 (15)
O2^vii—K—O3^ix	71.81 (13)	K^xvi—O2—Hg1	152.62 (18)
O3^viii—K—O3^ix	96.58 (11)	K^ix—O2—Hg1	106.08 (14)
O4—K—O1^x	70.83 (12)	S1—O2—K^iii	123.9 (2)
O3^ii—K—O1^x	92.15 (13)	K^xvi—O2—K^iii	76.81 (11)
O2^vii—K—O1^x	153.12 (14)	K^ix—O2—K^iii	102.76 (14)
O3^viii—K—O1^x	136.64 (14)	Hg1—O2—K^iii	77.81 (11)
O3^ix—K—O1^x	87.91 (12)	S1—O2—Hg1^xi	74.6 (2)
O4—K—O2^ix	142.15 (13)	K^xvi—O2—Hg1^xi	99.81 (13)
O3^ii—K—O2^ix	62.97 (12)	K^ix—O2—Hg1^xi	169.99 (15)
O2^vii—K—O2^ix	78.57 (12)	Hg1—O2—Hg1^xi	67.04 (10)
O3^viii—K—O2^ix	137.08 (13)	K^iii—O2—Hg1^xi	83.25 (11)
O3^ix—K—O2^ix	48.52 (12)	S1—O3—K^xi	111.4 (2)
O1^x—K—O2^ix	74.74 (13)	S1—O3—K^i	146.2 (2)
O4—K—O2^iv	85.91 (12)	K^xi—O3—K^i	93.16 (13)
O3^ii—K—O2^iv	165.93 (12)	S1—O3—K^ix	102.7 (2)
O2^vii—K—O2^iv	103.19 (11)	K^xi—O3—K^ix	119.66 (15)
O3^viii—K—O2^iv	65.78 (12)	K^i—O3—K^ix	83.42 (11)
O3^ix—K—O2^iv	59.64 (12)	S1—O3—Hg1	47.08 (14)
O1^x—K—O2^iv	80.18 (13)	K^xi—O3—Hg1	128.60 (16)
O2^ix—K—O2^iv	103.40 (12)	K^i—O3—Hg1	99.47 (12)
O4—K—O1^ii	78.00 (12)	K^ix—O3—Hg1	111.22 (15)
O3^ii—K—O1^ii	45.94 (10)	S2—O4—K	144.5 (2)
O2^vii—K—O1^ii	71.72 (13)	S2—O4—Hg2^iv	95.2 (2)
O3^viii—K—O1^ii	84.23 (12)	K—O4—Hg2^iv	106.36 (13)
O3^ix—K—O1^ii	139.21 (12)	S2—O4—Hg1^iv	125.7 (2)
O1^x—K—O1^ii	119.01 (14)	K—O4—Hg1^iv	88.05 (11)
O2^ix—K—O1^ii	106.27 (12)	Hg2^iv—O4—Hg1^iv	72.75 (9)
O2^iv—K—O1^ii	148.02 (11)	S2—O4—Hg2	44.44 (13)
O2—S1—O3	112.5 (3)	K—O4—Hg2	104.87 (13)
O2—S1—O1	112.5 (3)	Hg2^iv—O4—Hg2	94.51 (12)
O3—S1—O1	111.2 (3)	Hg1^iv—O4—Hg2	164.18 (16)
O2—S1—Hg1	107.4 (2)	S2—O4—Hg1^viii	86.66 (18)
O3—S1—Hg1	105.82 (17)	K—O4—Hg1^viii	95.24 (12)
O1—S1—Hg1	106.98 (18)	Hg2^iv—O4—Hg1^viii	137.74 (14)
O2—S1—Hg1^xi	81.5 (2)	Hg1^iv—O4—Hg1^viii	72.16 (10)
O3—S1—Hg1^xi	163.6 (2)	Hg2—O4—Hg1^viii	114.77 (12)
O1—S1—Hg1^xi	53.59 (19)	S2—O4—Hg1^xiv	75.96 (17)
Hg1—S1—Hg1^xi	76.40 (5)	K—O4—Hg1^xiv	139.47 (12)
O2—S1—Hg2^xi	136.9 (2)	Hg2^iv—O4—Hg1^xiv	56.67 (7)
O3—S1—Hg2^xi	109.2 (2)	Hg1^iv—O4—Hg1^xiv	52.80 (7)
O1—S1—Hg2^xi	38.99 (17)	Hg2—O4—Hg1^xiv	112.48 (12)
Hg1—S1—Hg2^xi	70.31 (5)	Hg1^viii—O4—Hg1^xiv	83.29 (9)
Hg1^xi—S1—Hg2^xi	55.70 (3)	S2—O4—Hg1^xiii	48.14 (15)
O6—S2—O4	110.7 (2)	K—O4—Hg1^xiii	143.72 (14)
O6—S2—O4^xii	110.7 (2)	Hg2^iv—O4—Hg1^xiii	104.32 (11)
O4—S2—O4^xii	111.0 (3)	Hg1^iv—O4—Hg1^xiii	82.94 (10)
O6—S2—Hg2	105.9 (2)	Hg2—O4—Hg1^xiii	91.47 (9)
O4—S2—Hg2	109.22 (18)	Hg1^viii—O4—Hg1^xiii	48.55 (6)
O4^xii—S2—Hg2	109.22 (18)	Hg1^xiv—O4—Hg1^xiii	51.82 (6)
O6—S2—Hg2^iv	153.5 (2)	Hg2—O5—Hg1^xii	114.25 (16)
O4—S2—Hg2^iv	59.08 (17)	Hg2—O5—Hg1	114.25 (16)
O4^xii—S2—Hg2^iv	59.08 (17)	Hg1^xii—O5—Hg1	103.9 (2)
Hg2—S2—Hg2^iv	100.67 (5)	Hg2—O5—Hg1^ii	93.07 (14)
O6—S2—Hg1^xiii	44.44 (15)	Hg1^xii—O5—Hg1^ii	141.4 (2)
O4—S2—Hg1^xiii	113.77 (18)	Hg1—O5—Hg1^ii	87.51 (9)
O4^xii—S2—Hg1^xiii	68.75 (18)	Hg2—O5—Hg1^vi	93.07 (14)
Hg2—S2—Hg1^xiii	134.36 (5)	Hg1^xii—O5—Hg1^vi	87.51 (9)
Hg2^iv—S2—Hg1^xiii	113.87 (5)	Hg1—O5—Hg1^vi	141.4 (2)
O6—S2—Hg1^viii	44.44 (15)	Hg1^ii—O5—Hg1^vi	63.19 (10)
O4—S2—Hg1^viii	68.75 (18)	S2—O6—Hg2^iii	148.3 (3)
O4^xii—S2—Hg1^viii	113.77 (18)	S2—O6—Hg1^viii	113.0 (2)
Hg2—S2—Hg1^viii	134.36 (5)	Hg2^iii—O6—Hg1^viii	91.71 (13)
Hg2^iv—S2—Hg1^viii	113.87 (5)	S2—O6—Hg1^xiii	113.0 (2)
Hg1^xiii—S2—Hg1^viii	55.34 (4)	Hg2^iii—O6—Hg1^xiii	91.71 (13)
O6—S2—Hg2^iii	20.5 (2)	Hg1^viii—O6—Hg1^xiii	75.24 (14)
O4—S2—Hg2^iii	119.08 (17)	S2—O6—Hg2	46.70 (16)
O4^xii—S2—Hg2^iii	119.08 (17)	Hg2^iii—O6—Hg2	101.55 (16)
Hg2—S2—Hg2^iii	85.33 (4)	Hg1^viii—O6—Hg2	140.31 (9)
Hg2^iv—S2—Hg2^iii	174.00 (5)	Hg1^xiii—O6—Hg2	140.31 (9)

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