An unexpected oxidation: NaK5Cl2(S2O6)2 revisited

Harrison, W.T.A.; Plater, M.J.

doi:10.1107/S2056989017000494

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Volume 73| Part 2| February 2017| Pages 188-191

https://doi.org/10.1107/S2056989017000494

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An unexpected oxidation: NaK₅Cl₂(S₂O₆)₂ revisited

William T. A. Harrison ^a ^* and M. John Plater ^a

^aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
^*Correspondence e-mail: w.harrison@abdn.ac.uk

Edited by M. Weil, Vienna University of Technology, Austria (Received 4 January 2017; accepted 10 January 2017; online 13 January 2017)

The title compound, NaK₅Cl₂(S₂O₆)₂ [systematic name: sodium pentapotassium dichloride bis(dithionate)], arose as an unexpected product from an organic synthesis that used dithionite (S₂O₄²⁻) ions as a reducing agent to destroy excess permanganate ions. Compared to the previous study [Stanley (1953 ). Acta Cryst. 6, 187–196], the present tetragonal structure exhibits a root 2a × root 2a × c super-cell due to subtle changes in the orientations of the dithionate anions. The structure can be visualized as a three-dimensional framework of [001] columns of alternating trans-NaO₄Cl₂ and KO₄Cl₂ octahedra cross-linked by the dithionate ions with the interstices occupied by KO₆Cl₂ polyhedra to generate a densely packed three-dimensional framework. The asymmetric unit comprises two sodium ions (site symmetries 4 and -4, four potassium ions (site symmetries = -4, 4, 1 and 1), three chloride ions (site symmetries = 4, 4 and 2) and two half-dithionate ions (all atoms on general positions). Both dithionate ions are completed by crystallographic inversion symmetry. The crystal chosen for data collection was found to be rotationally twinned by 180° about the [100] axis in reciprocal space with a 0.6298 (13):0.3702 (13) domain ratio.

Keywords: crystal structure; dithionate; super-cell; redetermination.

CCDC reference: 1526611

1. Chemical context

As well as their large-scale industrial use in reducing and solublizing vat dyes such as indigo (Božič & Kokol, 2008 ), dithionites containing the S₂O₄²⁻ anion (sulfur oxidation state = +3) have long found use as moderately strong reducing agents in organic synthesis (De Vries & Kellogg, 1980 , and references therein). The title mixed-cation, mixed-anion compound, NaK₅Cl₂(S₂O₆)₂ (I), containing S₂O₆²⁻ dithionate ions (sulfur oxidation state = +5), arose as a completely unexpected side product from an attempt to oxidize hexamethyl benzene to mellitic acid as a precursor of synthetic mellite (Plater & Harrison, 2015 ): sodium dithionite was added to the reaction to destroy excess permanganate ions (as KMnO₄) and the source of the chloride ions was added HCl. To our slight surprise, the structure of the title compound, along with that of the non-isostructural Na₂K₄Cl₂(S₂O₆)₂, was established over 60 years ago (Stanley, 1953). This re-determination presents a superstructure of the earlier reported structure, which arises from subtle orientational changes for the dithionate anions.

2. Structural commentary

Compound (I) comprises two sodium ions (Na1 site symmetry = 4, Na2 site symmetry = $[\overline{4}]$ ), four potassium ions (site symmetries = $[\overline{4}]$ , 4, 1 and 1 for K1, K2, K3 and K4, respectively), three chloride ions (Cl1 and Cl2 with site symmetry 4, Cl3 with site symmetry 2) and two half-dithionate ions (all atoms on general positions) in the asymmetric unit. Selected geometrical data are given in Table 1. Both S₂O₆²⁻ dithionate ions are completed by crystallographic inversion symmetry at the mid-points of their S—S bonds [S1—S1ⁱ = 2.1227 (9), S2—S2^xiii = 2.1176 (9) Å; see Table 1 for symmetry codes] and both exhibit almost ideal staggered conformations about their S—S bonds. The mean S—O bond length (both unique ions) is 1.45 Å and the narrow spread of individual S—O bond lengths from 1.4465 (11) to 1.4526 (13) Å indicates that the negative charges of the anion are delocalized over the three O atoms attached to each S atom (i.e.: we cannot identify localized S=O double bonds and S—O single bonds). In terms of the orientation of the dithionate ions in the unit cell, the S1—O1 bond deviates from the (001) plane by 12.5° and the S2—O5 bond deviates by 10.6° (vide infra).

Table 1
Selected bond lengths (Å)

Na1—O1ⁱ	2.3375 (13)	K3—Cl2	3.1088 (5)
Na1—Cl1ⁱⁱ	2.6942 (13)	K4—O2^viii	2.8429 (11)
Na1—Cl2	2.7260 (12)	K4—O6^vi	2.9235 (11)
Na2—O5ⁱⁱⁱ	2.3506 (13)	K4—O6^ix	2.9941 (11)
Na2—Cl3^iv	2.6986 (5)	K4—O4^x	3.0284 (12)
K1—O3^v	2.8262 (12)	K4—O3^xi	3.0290 (11)
K1—Cl3^iv	2.9976 (5)	K4—O2^xii	3.0664 (12)
K2—O6	2.8193 (11)	K4—Cl1	3.1168 (5)
K2—Cl2	2.9746 (8)	K4—Cl3^x	3.1291 (5)
K2—Cl1	2.9978 (9)	S1—O3	1.4465 (11)
K3—O4^v	2.7843 (11)	S1—O2	1.4507 (10)
K3—O2^v	2.8705 (11)	S1—O1	1.4526 (13)
K3—O4^vi	2.8973 (11)	S1—S1ⁱ	2.1227 (9)
K3—O3ⁱ	2.8995 (11)	S2—O6	1.4475 (11)
K3—O1^vii	2.9148 (11)	S2—O5	1.4505 (13)
K3—O5ⁱⁱⁱ	3.0176 (11)	S2—O4	1.4516 (10)
K3—Cl3^iv	3.0836 (5)	S2—S2^xiii	2.1176 (9)
Symmetry codes: (i) -x+1, -y+1, -z; (ii) x, y, z-1; (iii) $[x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+1]$ ; (iv) $[-y+{\script{3\over 2}}, x, z]$ ; (v) $[y, -x+{\script{1\over 2}}, z]$ ; (vi) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z]$ ; (vii) $[-y+1, x-{\script{1\over 2}}, -z]$ ; (viii) $[-y+1, x-{\script{1\over 2}}, -z+1]$ ; (ix) $[-y+{\script{1\over 2}}, x, z]$ ; (x) $[y-{\script{1\over 2}}, -x, -z+1]$ ; (xi) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z+1]$ ; (xii) $[x-{\script{1\over 2}}, y-{\script{1\over 2}}, -z+1]$ ; (xiii) -x, -y+1, -z+1.

The packing for (I) can be described in terms of pseudo layers lying perpendicular to the c-axis direction of the tetragonal unit cell. At z ∼ 0 and 1, the S1/O1/O2/O3 dithionate ion and the Na1 and K1 cations reside (Fig. 1); at z ∼1/2, are to be found the S2/O4/O5/O6 dithionate ion and Na2 and K2 (Fig. 2). Between them, at z ∼ 1/4 and 3/4, are K3, K4 and the three chloride ions, which form a distorted square grid (Fig. 3).

Figure 1
View down [001] of a slice (−0.15 ≤ z ≤ 0.15) of the structure of (I). Displacement ellipsoids are displayed at the 50% probability level. [Symmetry code: (i) 1 − x, 1 − y, −z.] Note that Na1 lies on a fourfold axis and K1 has $[\overline{4}]$ site symmetry.

Figure 2
View down [001] of a slice (0.35 ≤ z ≤ 0.65) of the structure of (I). Displacement ellipsoids are displayed at the 50% probability level. [Symmetry codes: (ii) −x, 1 − y, 1 − z; (iii) 1 − x, 1 − y, 1 − z.] Note that K2 lies on a fourfold axis and Na2 has $[\overline{4}]$ site symmetry.

Figure 3
View down [001] of a slice (0.25 ≤ z ≤ 0.35) of the structure of (I). Displacement ellipsoids are displayed at the 50% probability level. [Symmetry codes: (iii) 1 − x, 1 − y, 1 − z; (iv) $[{3\over 2}]$ − y, x, z; (v) $[{1\over 2}]$ − y, x, z; (vi) $[{1\over 2}]$ + y, 1 − x, 1 − z; (vii) $[{1\over 2}]$ + x, $[{1\over 2}]$ + y, 1 − z.] Note that Cl1 and Cl2 lie on fourfold axes and Cl3 lies on a twofold axis. The chloride ions link to the sodium and potassium ions shown in Figs. 1

and 2

to generate infinite stacks of alternating NaO₄Cl₂ and KO₄Cl₂ octahedra.

The extended structure of (I) can be visualized (Fig. 4) as [001] chains of alternating trans-NaO₄Cl₂ and KO₄Cl₂ octahedra linked via their chloride ions and cross-linked by the dithionate groups. There are two distinct chains: the Na1 and K2 species and their linking chloride ions (Cl1 and Cl2) lie on the fourfold axes at (1/4, 1/4, z) and (3/4, 3/4, z), whereas Na2 and K1 (both site symmetry $[\overline{4}]$ ) are connected by Cl3, which lies on the (1/4, 3/4, z) twofold axis and its symmetry-generated clone at (3/4, 1/4, z). As expected, the Na—O bonds (mean = 2.34 Å) are much shorter than the K—O bonds (mean = 2.82 Å). In terms of bond angles, the sodium-centred octahedra are almost regular [spread of cis and trans bond angles = 87.94 (4)–92.06 (4) and 175.89 (8)–180°, respectively, for Na1 and 86.02 (3)–93.98 (3) and 172.03 (5)–180°, respectively, for Na2] but the potassium-centred moieties are grossly distorted with ranges of cis and trans angles of 71.75 (2)–108.25 (2) and 143.50 (4)–180°, respectively, for K1 and 74.91 (2)–105.09 (2) and 149.82 (5)–180°, respectively, for K2.

Figure 4
Polyhedral view of the structure of (I), showing the [001] chains of NaO₄Cl₂ octahedra (blue) and KO₄Cl₂ (K1 and K2) octahedra (lilac) cross-linked by the dithionate groups. Atoms K3 and K4 are shown as purple spheres.

The structure of (I) is completed by the K3 and K4 potassium ions, which occupy interstices in the framework described in the preceding paragraph. The K3 coordination polyhedron approximates to an extremely distorted KO₆Cl₂ square anti-prism. The coordination for K4 is slightly ambiguous, with six shorter K—O bonds [2.8429 (11)–3.0664 (12) Å] and two K—Cl links [3.1168 (5) and 3.1291 (5) Å] forming a squashed and distorted square anti-prism. There are two further K4⋯O close contacts at 3.2273 (12) and 3.3822 (12) Å [the next-nearest K4⋯O separation after these is 4.3935 (13) Å] but given that these K4⋯O contacts are longer than the K4—Cl bonds and have bond valences (Brown & Altermatt, 1985 ) of less than 0.05 (Brown, 2002 ), we regard them as not significant. The three chloride ions each adopt almost regular ClK₅Na octahedral geometries.

Bond-valence sum (BVS) data (Brown & Altermatt, 1985) for the cations in (I) indicate that the sodium ions in (I) are considerably `overbonded': BVS(Na1) = 1.46 and BVS(Na2) = 1.45 (expected value = 1.0 valence units). Three of the potassium ions are possibly slightly over-bonded (BVS values for K1, K2 and K3 = 1.16, 1.19 and 1.19, respectively) whereas K4 (BVS = 1.01) achieves its expected valence almost exactly.

The previously-reported structure of NaK₅Cl₂(S₂O₆)₂ (Stanley, 1953) was modelled in space group P4/mnc [a_S = 8.5621 (6), c_S = 11.5288 (6) Å, V_S = 845.2 Å³; S = Stanley], thus it may be seen that the present unit cell is a $[\surd]$ 2a_S × $[\surd]$ 2a_S × c_S super-cell of the Stanley structure with doubled volume. The relative dispositions of the sodium, potassium and chloride ions in the Stanley structure are almost the same as in (I); the main difference occurs in the orientation of the dithionate ions with respect to the (001) plane; in the Stanley structure, this species, which is built up from one unique S atom and two unique O atoms, has 2/m (C_2h) point-group symmetry about the mid-point of the S—S bond with the S atom and one of the O atoms lying on the z = 0 mirror plane [compare the deviations from the (001) plane noted above for the S1—O1 and S2—O5 bonds in (I)].

3. Database survey

As already noted, this structure (ICSD reference number 24676) was previously reported by Stanley (1953). A survey of the Cambridge Structural Database (Groom et al., 2016 ) (entries updated to 20 December 2016) revealed 138 crystal structures containing dithionate anions.

4. Synthesis and crystallization

In an attempt to prepare mellitic acid (C₆H₆O₁₂) as a precursor of synthetic mellite (Plater & Harrison, 2015), hexamethylbenzene (2.0 g, 0.0123 moles) and KMnO₄ (23.4 g, 0.148 moles, 12 equiv.) were refluxed in water for 24 h (Friedel & Crafts, 1884 ): the organic starting material had a tendency to sublime into the condenser. After cooling, the mixture was treated with excess Na₂S₂O₄ to decompose the unreacted permanganate, which turned the solution brown. It was filtered and then treated with conc. HCl to give a pH of 1. After leaving to crystallize, the solid product (1.34 g) was collected by filtration as colourless blocks of (I). Evidently, dithionite has been oxidized by permanganate to dithionate by an unknown pathway and the sodium and potassium cations and chloride ions (from the hydrochloric acid) present in the mixture serendipitiously combine with the dithionate ions to form (I).

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. All the atoms in the asymmetric unit were located by SHELXT (Sheldrick, 2015a ): the potassium cations and chloride anions were distinguished in terms of chemically reasonable environments. The crystal chosen for data collection was found to be rotationally twinned by 180° about the [100] axis in reciprocal space with a 0.6298 (13):0.3702 (13) domain ratio.

Table 2
Experimental details

Crystal data
Chemical formula	NaK₅Cl₂(S₂O₆)₂
M_r	609.63
Crystal system, space group	Tetragonal, P4/n
Temperature (K)	100
a, c (Å)	12.0421 (1), 11.3925 (2)
V (Å³)	1652.05 (4)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	2.24
Crystal size (mm)	0.05 × 0.02 × 0.02

Data collection
Diffractometer	Rigaku Mercury CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 2004 )
T_min, T_max	0.911, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	1910, 1910, 1834
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.015, 0.043, 1.06
No. of reflections	1910
No. of parameters	113
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.35
Computer programs: CrystalClear (Rigaku, 2010 ), SHELXT (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b ), ORTEP-3 for Windows (Farrugia, 2012 ) and ATOMS (Dowty, 1999 ).

Supporting information

CCDC reference: 1526611

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S2056989017000494/wm5357sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989017000494/wm5357Isup2.hkl

checkCIF report

Computing details top

Data collection: CrystalClear (Rigaku, 2010); cell refinement: CrystalClear (Rigaku, 2010); data reduction: CrystalClear (Rigaku, 2010); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and ATOMS (Dowty, 1999); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b).

Sodium pentapotassium dichloride bis(dithionate) top

Crystal data top

NaK₅Cl₂(S₂O₆)₂	D_x = 2.451 Mg m⁻³
M_r = 609.63	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/n	Cell parameters from 23162 reflections
a = 12.0421 (1) Å	θ = 2.3–27.5°
c = 11.3925 (2) Å	µ = 2.24 mm⁻¹
V = 1652.05 (4) Å³	T = 100 K
Z = 4	Block, colourless
F(000) = 1200	0.05 × 0.02 × 0.02 mm

Data collection top

Rigaku Mercury CCD diffractometer	1834 reflections with I > 2σ(I)
ω scans	θ_max = 27.5°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −10→11
T_min = 0.911, T_max = 1.000	k = −15→15
1910 measured reflections	l = −14→14
1910 independent reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F² > 2σ(F²)] = 0.015	w = 1/[σ²(F_o²) + (0.0242P)² + 0.4886P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.043	(Δ/σ)_max < 0.001
S = 1.06	Δρ_max = 0.35 e Å⁻³
1910 reflections	Δρ_min = −0.35 e Å⁻³
113 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. Refined as a 2-component twin.

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

	x	y	z	U_iso*/U_eq
Na1	0.2500	0.2500	0.01268 (9)	0.0094 (3)
Na2	0.7500	0.2500	0.5000	0.0084 (3)
K1	0.7500	0.2500	0.0000	0.01621 (19)
K2	0.2500	0.2500	0.51306 (5)	0.01506 (18)
K3	0.50130 (4)	0.19113 (2)	0.24632 (3)	0.01042 (8)
K4	0.18440 (2)	0.00129 (4)	0.74572 (3)	0.01187 (8)
S1	0.51535 (4)	0.58649 (4)	0.00758 (3)	0.00962 (10)
O1	0.63276 (11)	0.59544 (11)	−0.02005 (10)	0.0160 (3)
O2	0.48827 (9)	0.61202 (9)	0.12870 (9)	0.0163 (2)
O3	0.44243 (10)	0.63754 (9)	−0.07768 (9)	0.0190 (2)
S2	0.08586 (4)	0.51687 (4)	0.49086 (3)	0.00872 (10)
O4	0.10996 (9)	0.48723 (9)	0.37002 (9)	0.0152 (2)
O5	0.09283 (11)	0.63505 (10)	0.51433 (9)	0.0142 (3)
O6	0.13966 (9)	0.44729 (9)	0.57748 (9)	0.0169 (2)
Cl1	0.2500	0.2500	0.77619 (6)	0.00944 (14)
Cl2	0.2500	0.2500	0.25196 (5)	0.00958 (16)
Cl3	0.2500	0.7500	0.26312 (4)	0.00951 (13)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.0200 (3)	0.0200 (3)	0.0086 (3)	0.000	0.000	0.000
K2	0.0183 (3)	0.0183 (3)	0.0086 (3)	0.000	0.000	0.000
K3	0.00940 (15)	0.01049 (13)	0.01136 (15)	0.00021 (17)	0.00028 (9)	−0.00154 (12)
K4	0.01177 (13)	0.00978 (15)	0.01406 (15)	−0.00037 (17)	−0.00130 (13)	0.00016 (10)
Na1	0.0094 (5)	0.0094 (5)	0.0095 (5)	0.000	0.000	0.000
Na2	0.0080 (5)	0.0080 (5)	0.0090 (5)	0.000	0.000	0.000
S1	0.0104 (2)	0.0092 (2)	0.00920 (16)	−0.00190 (19)	0.00093 (11)	−0.00018 (12)
O1	0.0137 (7)	0.0134 (6)	0.0208 (5)	−0.0041 (6)	0.0057 (4)	−0.0037 (5)
O2	0.0201 (6)	0.0156 (5)	0.0131 (5)	−0.0047 (5)	0.0054 (5)	−0.0053 (4)
O3	0.0211 (6)	0.0137 (5)	0.0223 (6)	−0.0004 (5)	−0.0074 (5)	0.0047 (5)
S2	0.0080 (2)	0.0088 (2)	0.00928 (16)	−0.00075 (18)	0.00053 (12)	−0.00015 (12)
O4	0.0139 (5)	0.0188 (6)	0.0129 (5)	−0.0036 (5)	0.0053 (4)	−0.0044 (4)
O5	0.0134 (7)	0.0091 (6)	0.0200 (5)	−0.0031 (5)	0.0024 (4)	−0.0026 (4)
O6	0.0129 (5)	0.0176 (6)	0.0202 (5)	−0.0001 (5)	−0.0040 (4)	0.0061 (5)
Cl1	0.0100 (2)	0.0100 (2)	0.0084 (3)	0.000	0.000	0.000
Cl2	0.0099 (2)	0.0099 (2)	0.0090 (3)	0.000	0.000	0.000
Cl3	0.0107 (3)	0.0093 (2)	0.0085 (2)	0.00012 (15)	0.000	0.000

Geometric parameters (Å, º) top

Na1—O1ⁱ	2.3375 (13)	K4—O5^xiv	3.2273 (12)
Na1—O1ⁱⁱ	2.3375 (13)	K4—O1^xvi	3.3822 (12)
Na1—O1ⁱⁱⁱ	2.3375 (13)	S1—O3	1.4465 (11)
Na1—O1^iv	2.3375 (13)	S1—O2	1.4507 (10)
Na1—Cl1^v	2.6942 (13)	S1—O1	1.4526 (13)
Na1—Cl2	2.7260 (12)	S1—S1ⁱ	2.1227 (9)
Na2—O5^vi	2.3506 (13)	O1—Na1ⁱ	2.3375 (13)
Na2—O5^vii	2.3506 (13)	O1—K3^xvii	2.9148 (11)
Na2—O5^viii	2.3506 (13)	O1—K4^xviii	3.3822 (12)
Na2—O5^ix	2.3506 (13)	O2—K4^xix	2.8429 (11)
Na2—Cl3^ix	2.6986 (5)	O2—K3^xi	2.8705 (11)
Na2—Cl3^vii	2.6986 (5)	O2—K4^xviii	3.0664 (12)
K1—O3^viii	2.8262 (12)	O3—K1ⁱ	2.8262 (12)
K1—O3^ix	2.8262 (12)	O3—K3ⁱ	2.8995 (11)
K1—O3^x	2.8262 (12)	O3—K4^xx	3.0290 (11)
K1—O3ⁱ	2.8262 (12)	S2—O6	1.4475 (11)
K1—Cl3^ix	2.9976 (5)	S2—O5	1.4505 (13)
K1—Cl3ⁱ	2.9976 (5)	S2—O4	1.4516 (10)
K2—O6	2.8193 (11)	S2—S2^xxi	2.1176 (9)
K2—O6^viii	2.8193 (12)	O4—K3^xi	2.7843 (11)
K2—O6^xi	2.8193 (12)	O4—K3^xii	2.8973 (11)
K2—O6^xii	2.8193 (11)	O4—K4^xxii	3.0284 (12)
K2—Cl2	2.9746 (8)	O5—Na2^vii	2.3506 (13)
K2—Cl1	2.9978 (9)	O5—K3^xxiii	3.0176 (11)
K3—O4^viii	2.7843 (11)	O5—K4^xxii	3.2273 (12)
K3—O2^viii	2.8705 (11)	O6—K4^xii	2.9235 (11)
K3—O4^xii	2.8973 (11)	O6—K4^viii	2.9941 (11)
K3—O3ⁱ	2.8995 (11)	Cl1—Na1^xxiv	2.6943 (13)
K3—O1ⁱⁱⁱ	2.9148 (11)	Cl1—K4^xii	3.1168 (5)
K3—O5^vi	3.0176 (11)	Cl1—K4^viii	3.1168 (5)
K3—Cl3^ix	3.0836 (5)	Cl1—K4^xi	3.1168 (5)
K3—Cl2	3.1088 (5)	Cl2—K3^viii	3.1088 (5)
K4—O2^xiii	2.8429 (11)	Cl2—K3^xi	3.1088 (5)
K4—O6^xii	2.9235 (11)	Cl2—K3^xii	3.1088 (5)
K4—O6^xi	2.9941 (11)	Cl3—Na2^vii	2.6987 (5)
K4—O4^xiv	3.0284 (12)	Cl3—K1ⁱ	2.9976 (5)
K4—O3^xv	3.0290 (11)	Cl3—K3^xi	3.0835 (5)
K4—O2^xvi	3.0664 (12)	Cl3—K3^xxv	3.0835 (5)
K4—Cl1	3.1168 (5)	Cl3—K4^xxii	3.1291 (5)
K4—Cl3^xiv	3.1291 (5)	Cl3—K4^xix	3.1291 (5)

O1ⁱ—Na1—O1ⁱⁱ	175.89 (8)	O6^xii—K4—Cl3^xiv	90.04 (2)
O1ⁱ—Na1—O1ⁱⁱⁱ	89.926 (3)	O6^xi—K4—Cl3^xiv	130.64 (2)
O1ⁱⁱ—Na1—O1ⁱⁱⁱ	89.926 (3)	O4^xiv—K4—Cl3^xiv	75.88 (2)
O1ⁱ—Na1—O1^iv	89.926 (3)	O3^xv—K4—Cl3^xiv	67.35 (2)
O1ⁱⁱ—Na1—O1^iv	89.926 (3)	O2^xvi—K4—Cl3^xiv	129.05 (2)
O1ⁱⁱⁱ—Na1—O1^iv	175.89 (8)	Cl1—K4—Cl3^xiv	150.327 (9)
O1ⁱ—Na1—Cl1^v	92.06 (4)	O2^xiii—K4—O5^xiv	126.97 (3)
O1ⁱⁱ—Na1—Cl1^v	92.06 (4)	O6^xii—K4—O5^xiv	66.79 (3)
O1ⁱⁱⁱ—Na1—Cl1^v	92.06 (4)	O6^xi—K4—O5^xiv	60.67 (3)
O1^iv—Na1—Cl1^v	92.06 (4)	O4^xiv—K4—O5^xiv	45.62 (3)
O1ⁱ—Na1—Cl2	87.94 (4)	O3^xv—K4—O5^xiv	108.85 (3)
O1ⁱⁱ—Na1—Cl2	87.94 (4)	O2^xvi—K4—O5^xiv	116.05 (3)
O1ⁱⁱⁱ—Na1—Cl2	87.94 (4)	Cl1—K4—O5^xiv	119.10 (3)
O1^iv—Na1—Cl2	87.94 (4)	Cl3^xiv—K4—O5^xiv	71.17 (3)
Cl1^v—Na1—Cl2	180.0	O2^xiii—K4—O1^xvi	73.26 (3)
O5^vi—Na2—O5^vii	172.03 (5)	O6^xii—K4—O1^xvi	131.92 (3)
O5^vi—Na2—O5^viii	90.277 (4)	O6^xi—K4—O1^xvi	107.92 (3)
O5^vii—Na2—O5^viii	90.277 (4)	O4^xiv—K4—O1^xvi	113.99 (3)
O5^vi—Na2—O5^ix	90.277 (4)	O3^xv—K4—O1^xvi	58.57 (3)
O5^vii—Na2—O5^ix	90.277 (4)	O2^xvi—K4—O1^xvi	44.07 (3)
O5^viii—Na2—O5^ix	172.03 (5)	Cl1—K4—O1^xvi	67.76 (3)
O5^vi—Na2—Cl3^ix	86.02 (3)	Cl3^xiv—K4—O1^xvi	113.60 (2)
O5^vii—Na2—Cl3^ix	86.02 (3)	O5^xiv—K4—O1^xvi	158.77 (2)
O5^viii—Na2—Cl3^ix	93.98 (3)	O3—S1—O2	114.34 (7)
O5^ix—Na2—Cl3^ix	93.98 (3)	O3—S1—O1	114.44 (7)
O5^vi—Na2—Cl3^vii	93.98 (3)	O2—S1—O1	114.16 (7)
O5^vii—Na2—Cl3^vii	93.98 (3)	O3—S1—S1ⁱ	104.87 (6)
O5^viii—Na2—Cl3^vii	86.02 (3)	O2—S1—S1ⁱ	104.25 (5)
O5^ix—Na2—Cl3^vii	86.02 (3)	O1—S1—S1ⁱ	102.99 (6)
Cl3^ix—Na2—Cl3^vii	180.0	S1—O1—Na1ⁱ	129.73 (8)
O3^viii—K1—O3^ix	143.50 (4)	S1—O1—K3^xvii	113.37 (6)
O3^viii—K1—O3^x	95.627 (13)	Na1ⁱ—O1—K3^xvii	101.79 (5)
O3^ix—K1—O3^x	95.627 (13)	S1—O1—K4^xviii	87.35 (5)
O3^viii—K1—O3ⁱ	95.627 (13)	Na1ⁱ—O1—K4^xviii	97.05 (5)
O3^ix—K1—O3ⁱ	95.627 (13)	K3^xvii—O1—K4^xviii	129.71 (5)
O3^x—K1—O3ⁱ	143.50 (4)	S1—O2—K4^xix	130.46 (6)
O3^viii—K1—Cl3^ix	108.25 (2)	S1—O2—K3^xi	120.98 (6)
O3^ix—K1—Cl3^ix	108.25 (2)	K4^xix—O2—K3^xi	101.95 (3)
O3^x—K1—Cl3^ix	71.75 (2)	S1—O2—K4^xviii	100.28 (6)
O3ⁱ—K1—Cl3^ix	71.75 (2)	K4^xix—O2—K4^xviii	95.61 (3)
O3^viii—K1—Cl3ⁱ	71.75 (2)	K3^xi—O2—K4^xviii	99.20 (3)
O3^ix—K1—Cl3ⁱ	71.75 (2)	S1—O3—K1ⁱ	119.41 (6)
O3^x—K1—Cl3ⁱ	108.25 (2)	S1—O3—K3ⁱ	127.26 (6)
O3ⁱ—K1—Cl3ⁱ	108.25 (2)	K1ⁱ—O3—K3ⁱ	93.33 (3)
Cl3^ix—K1—Cl3ⁱ	180.0	S1—O3—K4^xx	121.17 (6)
O6—K2—O6^viii	86.115 (12)	K1ⁱ—O3—K4^xx	93.38 (3)
O6—K2—O6^xi	86.115 (12)	K3ⁱ—O3—K4^xx	94.04 (3)
O6^viii—K2—O6^xi	149.82 (5)	O6—S2—O5	114.61 (7)
O6—K2—O6^xii	149.82 (5)	O6—S2—O4	114.50 (7)
O6^viii—K2—O6^xii	86.115 (12)	O5—S2—O4	113.86 (7)
O6^xi—K2—O6^xii	86.115 (12)	O6—S2—S2^xxi	105.01 (5)
O6—K2—Cl2	105.09 (2)	O5—S2—S2^xxi	103.10 (6)
O6^viii—K2—Cl2	105.09 (2)	O4—S2—S2^xxi	103.96 (5)
O6^xi—K2—Cl2	105.09 (2)	S2—O5—Na2^vii	127.70 (8)
O6^xii—K2—Cl2	105.09 (2)	S2—O5—K3^xxiii	111.41 (6)
O6—K2—Cl1	74.91 (2)	Na2^vii—O5—K3^xxiii	103.01 (4)
O6^viii—K2—Cl1	74.91 (2)	S2—O5—K4^xxii	89.49 (5)
O6^xi—K2—Cl1	74.91 (2)	Na2^vii—O5—K4^xxii	96.35 (4)
O6^xii—K2—Cl1	74.91 (2)	K3^xxiii—O5—K4^xxii	131.31 (5)
Cl2—K2—Cl1	180.0	S2—O6—K2	121.42 (6)
O4^viii—K3—O2^viii	155.78 (4)	S2—O6—K4^xii	130.44 (6)
O4^viii—K3—O4^xii	111.31 (5)	K2—O6—K4^xii	90.43 (3)
O2^viii—K3—O4^xii	83.34 (3)	S2—O6—K4^viii	119.60 (6)
O4^viii—K3—O3ⁱ	74.78 (3)	K2—O6—K4^viii	89.00 (3)
O2^viii—K3—O3ⁱ	96.76 (3)	K4^xii—O6—K4^viii	95.50 (3)
O4^xii—K3—O3ⁱ	163.31 (3)	Na1^xxiv—Cl1—K2	180.0
O4^viii—K3—O1ⁱⁱⁱ	129.10 (4)	Na1^xxiv—Cl1—K4	96.394 (14)
O2^viii—K3—O1ⁱⁱⁱ	65.88 (3)	K2—Cl1—K4	83.606 (14)
O4^xii—K3—O1ⁱⁱⁱ	93.82 (3)	Na1^xxiv—Cl1—K4^xii	96.394 (14)
O3ⁱ—K3—O1ⁱⁱⁱ	71.28 (3)	K2—Cl1—K4^xii	83.606 (14)
O4^viii—K3—O5^vi	75.96 (3)	K4—Cl1—K4^xii	167.21 (3)
O2^viii—K3—O5^vi	94.81 (3)	Na1^xxiv—Cl1—K4^viii	96.394 (14)
O4^xii—K3—O5^vi	64.12 (3)	K2—Cl1—K4^viii	83.606 (14)
O3ⁱ—K3—O5^vi	132.27 (4)	K4—Cl1—K4^viii	89.290 (3)
O1ⁱⁱⁱ—K3—O5^vi	153.02 (3)	K4^xii—Cl1—K4^viii	89.289 (3)
O4^viii—K3—Cl3^ix	80.21 (2)	Na1^xxiv—Cl1—K4^xi	96.394 (14)
O2^viii—K3—Cl3^ix	75.58 (2)	K2—Cl1—K4^xi	83.606 (14)
O4^xii—K3—Cl3^ix	126.11 (2)	K4—Cl1—K4^xi	89.289 (3)
O3ⁱ—K3—Cl3^ix	69.55 (2)	K4^xii—Cl1—K4^xi	89.289 (3)
O1ⁱⁱⁱ—K3—Cl3^ix	119.90 (3)	K4^viii—Cl1—K4^xi	167.21 (3)
O5^vi—K3—Cl3^ix	68.94 (3)	Na1—Cl2—K2	180.0
O4^viii—K3—Cl2	74.58 (2)	Na1—Cl2—K3	88.815 (12)
O2^viii—K3—Cl2	129.30 (2)	K2—Cl2—K3	91.185 (12)
O4^xii—K3—Cl2	73.07 (2)	Na1—Cl2—K3^viii	88.814 (12)
O3ⁱ—K3—Cl2	94.52 (3)	K2—Cl2—K3^viii	91.186 (12)
O1ⁱⁱⁱ—K3—Cl2	71.59 (3)	K3—Cl2—K3^viii	89.976 (1)
O5^vi—K3—Cl2	112.82 (3)	Na1—Cl2—K3^xi	88.815 (12)
Cl3^ix—K3—Cl2	153.089 (9)	K2—Cl2—K3^xi	91.185 (12)
O2^xiii—K4—O6^xii	73.54 (3)	K3—Cl2—K3^xi	89.975 (1)
O2^xiii—K4—O6^xi	144.06 (3)	K3^viii—Cl2—K3^xi	177.63 (2)
O6^xii—K4—O6^xi	81.16 (4)	Na1—Cl2—K3^xii	88.814 (12)
O2^xiii—K4—O4^xiv	150.56 (4)	K2—Cl2—K3^xii	91.186 (12)
O6^xii—K4—O4^xiv	112.11 (3)	K3—Cl2—K3^xii	177.63 (2)
O6^xi—K4—O4^xiv	63.40 (3)	K3^viii—Cl2—K3^xii	89.975 (1)
O2^xiii—K4—O3^xv	94.02 (3)	K3^xi—Cl2—K3^xii	89.975 (1)
O6^xii—K4—O3^xv	156.61 (4)	Na2^vii—Cl3—K1ⁱ	180.0
O6^xi—K4—O3^xv	117.73 (3)	Na2^vii—Cl3—K3^xi	93.559 (11)
O4^xiv—K4—O3^xv	69.49 (3)	K1ⁱ—Cl3—K3^xi	86.441 (11)
O2^xiii—K4—O2^xvi	116.96 (4)	Na2^vii—Cl3—K3^xxv	93.559 (11)
O6^xii—K4—O2^xvi	140.54 (3)	K1ⁱ—Cl3—K3^xxv	86.441 (11)
O6^xi—K4—O2^xvi	69.44 (3)	K3^xi—Cl3—K3^xxv	172.88 (2)
O4^xiv—K4—O2^xvi	77.97 (3)	Na2^vii—Cl3—K4^xxii	91.846 (11)
O3^xv—K4—O2^xvi	62.72 (3)	K1ⁱ—Cl3—K4^xxii	88.154 (10)
O2^xiii—K4—Cl1	77.20 (2)	K3^xi—Cl3—K4^xxii	88.576 (7)
O6^xii—K4—Cl1	71.69 (2)	K3^xxv—Cl3—K4^xxii	91.195 (7)
O6^xi—K4—Cl1	70.78 (2)	Na2^vii—Cl3—K4^xix	91.846 (10)
O4^xiv—K4—Cl1	132.25 (2)	K1ⁱ—Cl3—K4^xix	88.154 (10)
O3^xv—K4—Cl1	125.74 (3)	K3^xi—Cl3—K4^xix	91.195 (7)
O2^xvi—K4—Cl1	74.06 (2)	K3^xxv—Cl3—K4^xix	88.576 (7)
O2^xiii—K4—Cl3^xiv	75.23 (2)	K4^xxii—Cl3—K4^xix	176.31 (2)

Symmetry codes: (i) −x+1, −y+1, −z; (ii) x−1/2, y−1/2, −z; (iii) −y+1, x−1/2, −z; (iv) y−1/2, −x+1, −z; (v) x, y, z−1; (vi) x+1/2, y−1/2, −z+1; (vii) −x+1, −y+1, −z+1; (viii) y, −x+1/2, z; (ix) −y+3/2, x, z; (x) x+1/2, y−1/2, −z; (xi) −y+1/2, x, z; (xii) −x+1/2, −y+1/2, z; (xiii) −y+1, x−1/2, −z+1; (xiv) y−1/2, −x, −z+1; (xv) −x+1/2, −y+1/2, z+1; (xvi) x−1/2, y−1/2, −z+1; (xvii) y+1/2, −x+1, −z; (xviii) x+1/2, y+1/2, −z+1; (xix) y+1/2, −x+1, −z+1; (xx) −x+1/2, −y+1/2, z−1; (xxi) −x, −y+1, −z+1; (xxii) −y, x+1/2, −z+1; (xxiii) x−1/2, y+1/2, −z+1; (xxiv) x, y, z+1; (xxv) y, −x+3/2, z.

Acknowledgements

We thank the EPSRC National Crystallography Service (University of Southampton) for the X-ray data collection.

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