A new polymorph of dichlorido­triphenyl­anti­mony

In a new polymorphic form of dichloridotriphenyl­anti­mony, [Sb(C₆H₅)₃Cl₂], there are two crystallographically unique mol­ecules in the asymmetric unit and it has been determined that this polymorph is one of two kinetically favoured phases of pure dichloridotriphenyl­anti­mony, both of which have Z' > 1. A third polymorph, corresponding to (C₆H₅)₃SbCl_1.8F_0.2, is also known and has Z' = 2. By contrast, the thermodynamically preferred polymorph of pure (C₆H₅)₃SbCl₂ has Z' = 1. A brief comparison of the known polymorphic forms of dichloridotriphenyl­anti­mony is presented.

S1. Comment

Dichloridotriphenylantimony (I) is a versatile, commercially available compound. It is primarily used as a starting material in organostibene chemistry (Alonzo et al.,1996), including the preparation of polynuclear antimony complexes (Chandrasekhar & Thirumoorthi, 2009) and carboxylate-containing derivatives of antimony (Li et al., 2001; Quan et al., 2009). The latter are of particular interest since they may have antitumour activity (Li et al., 2001). Condensation polymers of (I) with Lewis bases are potent antibacterial agents (Carraher et al.,1983) and have been suggested as possible anticancer drugs (Siegmann-Louda et al., 2001).

Three different polymorphic forms of (I) are currently known. Polymorph (Ia), the first to be structurally characterized, crystallizes in P2₁2₁2₁ (Polynova & Porai-Koshits, 1966). In the original report, the five-coordinate geometry of (I) was confirmed, with chlorine atoms in apical positions of a trigonal– bipyramid and phenyl groups occupying the equatorial sites. An improved structural determination of polymorph (Ia), with a reassignment of cell axes, has since been reported (Begley & Sowerby, 1993). In an attempt to isolate the mixed halide complex (C₆H₅)₃SbClF, Sowerby and co-workers found a second orthorhombic polymorph (Ib), also in P2₁2₁2₁, but with two molecules in the asymmetric unit (Bone et al.,1992). To be more accurate, the molecule isolated in (Ib) corresponds to (C₆H₅)₃SbCl_1.8F_0.2, which may account for the observed doubling of the unit-cell volume. A third polymorph (Ic), with Z' = 4 in Pbca, has also been reported (Belyaev et al., 2002). It was postulated that (Ic) was formed from the decomposition of a binuclear osmium complex of composition [Os₂^IV(µ-O)(µ-O₂CCH₃)₂Cl₄(SbPh₃)₂].

We now report the structure (with data collected at 150 K, Table 1) of a new polymorph (Id) , recovered as a minority species from the flash distillation of an acetonitrile solution of (I). Because the data for the other polymorphs were collected at ambient temperature, a unit cell for (Id) was determined at room temperature confirming that it is not a low-temperature phase of (I). In order to further explore the nature of these various polymorphs, a few simple crystal growth trials were performed and the unit cells were determined for representative samples of each observed crystal habit in the resulting solids. We have found that crystals grown by slow evaporation of either a methylene chloride or an acetonitrile solution of (I) produce polymorph (Ia) exclusively. By contrast, crystals grown by flash distillation of the solvent from an acetonitrile solution of (I) result in the formation of colourless crystals of three different habits: needles, rods and plates. By visual inspection, the majority of the sample appears to be the colourless needles, identified as phase (Ia); however there are also colourless rods corresponding to (Ic) and colourless plates of the title compound, (Id). We believe this indicates that (Ia) is the thermodynamically preferred polymorph, while (Ic)and (Id) are both kinetically favoured. This is consistent with the simple packing motif of phase (Ia) and the absence of very large or very small torsion angles in phenyl ring positions relative to the equatorial plane of the molecule (vide infra).

In all four polymorphs, (I) has the same trigonal–bipyramidal coordination geometry (Fig. 1). There is very little deviation in the Cl—Sb—Cl bond angle [ranging from 175.55 (8) to 178.716 (19)°], but differences in the orientation of the phenyl rings are observed. In particular, there is significant variation among the angles observed between the mean plane of the phenyl rings (as defined by the six C atoms) and the mean equatorial plane of the molecules (as defined by the Sb atom and the three coordinating C atoms of the phenyl rings). These angles illustrate the extent to which the phenyl rings are rotated out of the equatorial plane of the molecule. Most of these angles have values of approximately 35° [24.96 (11) to 41.4 (6)°; average 35.0°] or approximately 55° [47.01 (11) to 66.2 (9)°; average 54.8°]. There are several exceptions, however, wherein a phenyl ring lies approximately perpendicular to the equatorial plane of the molecule [86.6 (9)°] or lies approximately in the equatorial plane of the molecule [6.51 (11), 10.9 (7), and13.3(7)°]. A complete list of these angles can be found in Table 2. Another indicator of strained or unusual molecular geometry is the angle made by the Sb atom, the coordinating C atom of a phenyl ring, and the C atom in the para position of the same phenyl ring. This parameter illustrates the extent to which a phenyl ring is bent out of the equatorial plane of the molecule. There is little deviation from the ideal 180° in any of these polymorphs. The values range from 174.9 (3) to 179.9 (4)°.

Polymorph (Ia), wherein Z' = 1, is the simplest structure. The phenyl groups form a 'propeller'-type arrangement, with all three rings tilted in the same direction. Thus, only one enantiomer exists in the crystal. The disordered Cl/F polymorph (Ib) has two crystallographically unique molecules in the asymmetric unit. One of these molecules exhibits the simple 'propeller' conformation seen in (Ia), while the other has one phenyl ring lying roughly perpendicular to the equatorial plane. Polymorph (Ic), wherein Z' = 4, is more complex still. All four crystallographically unique molecules deviate from a simple 'propeller' arrangement of phenyl groups. In two of the four molecules (containing Sb1 and Sb4), the mean plane of one phenyl ring is roughly in the equatorial plane of the molecule. In three of the four molecules (containing Sb1, Sb2, and Sb3), the phenyl rings are not all tilted in the same direction. The new polymorph (Id) has two crystallographically unique molecules in the asymmetric unit. Again, neither molecule can be described as having a 'propeller' arrangement of phenyl rings. In one of the molecules, the mean plane of one phenyl ring is roughly in the equatorial plane of the molecule, and in both molecules the phenyl rings that are rotated out of the equatorial plane are not all tilted in the same direction.

Fig. 2 shows comparable diagrams of the packing of (Ia), (Ic) and (Id), viewed approximately down the Cl—Sb—Cl axes. Polymorph (Ib) is not shown since the packing is haphazard due to the Cl/F disorder and this polymorph has not been observed for a pure sample of (I). Polymorph (Ia) arises from columnar packing of molecules along [100]. The molecules within a column are spaced by one cell length along the a axis [10.882 (4) Å], thus there are no close contacts between molecules in a column. Molecules in neighbouring columns are staggered by 1/2 of the unit-cell length. Polymorph (Id) shows a similar columnar packing scheme along [010], with separate columns of molecules containing Sb1 only and containing Sb2 only, and spacing of one cell length [10.0348 (3) Å] between molecules within a column. The molecules in neighbouring Sb1 columns and Sb2 columns are also staggered along the stacking direction. In contrast, polymorph (Ic) has quasi-columnar arrays, but the packing is significantly more complex. Molecules containing the Sb1 and Sb4 atoms alternate, respectively, in columns along [001] at positions z, z + 0.5, z + 1 etc. [c axis 43.823 (8) Å]. As a crude measure of the spacing between neighbouring molecules, we can look at the distance between the antimony atoms. The distance between an Sb1 atom and the next Sb4 atom within a column alternates between 10.775 (3) and 11.143 (3) Å. As viewed down [001], the Sb2 and Sb3 containing molecules pack in mixed pairs rather than columns. The distance between the Sb2 atom and Sb3 atom within a pair is 10.813 (3) Å. Polymorphs (Ia) and (Id) are in non-centrosymmetric space groups, consistent with the regular columnar packing. Packing in Fig. 2(a) (Ia) shows a head-to-tail arrangement between the phenyl rings of adjacent columns whereas Fig. 2(c) (Id) shows a head-to-head configuration. Polymorph (Ic) shows a mixed arrangement including a change of direction mid-cell that is consistent with the centrosymmetric space group.

Polymorphism is of interest to the pharmaceutical industry and, as such, is growing in general importance (Blagden & Davey, 2003). Recent studies suggest that polymorphism is relatively common for molecular organic species (Stahly, 2007) and perhaps more so for organometallic species (Braga & Grepioni, 2000). Dichloridotriphenylantimony provides an interesting example of an organometallic species that exists in several polymorphic forms and exhibits some degree of conformational polymorphism due to the positions adopted by the phenyl rings. Evidence suggests that the thermodynamically preferred form is both the simplest packing motif and the simplest conformational structure, having one molecule per asymmetric unit and a propeller-like arrangement of the phenyl rings. The kinetically favoured forms have multiple molecules in the asymmetric unit and include phenyl ring conformations that cannot be described as a simple propeller-like arrangement.

Related literature

For related literature, see: Alonzo et al. (1996); Belyaev et al. (2002); Blagden & Davey (2003); Bone et al. (1992); Braga & Grepioni (2000); Carraher, Naas, Giron & Cerutis (1983); Chandrasekhar & Thirumoorthi (2009); Li et al. (2001); Polynova & Porai-Koshits (1966); Quan et al. (2009); Siegmann-Louda, Carraher, Pflueger & Nagy (2001); Stahly (2007).

S2. Experimental

Dichloridotriphenylantimony was purchased from Aldrich and used as received. The methylene chloride and acetonitrile solvents used in the crystallization trials of (I) were purchased from Caledon as HPLC grade and used as received.

S3. Refinement

H atoms were positioned geometrically and refined using a riding model with C—H = 0.95 Å and with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: APEX2 (Bruker Nonius, 2008); cell refinement: APEX2 (Bruker Nonius, 2008) and SAINT (Bruker Nonius, 2008); data reduction: SAINT (Bruker Nonius, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009); software used to prepare material for publication: XP in SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures

	Fig. 1. The two crystallographically unique molecules of polmorph (Id) are presented. All displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Crystal packing is illustrated, showing select molecules in the unit cell for clarity. (a) In polymorph (Ia), the molecules are viewed down the a axis. (b) In polymorph (Ic), the view is down the c axis showing how the pairs of Sb complexes pack in two different styles. (c) In polymorph (Id), the respective columns of Sb1 and Sb2 are shown packing along the b axis.

dichloridotriphenylantimony

Crystal data

[Sb(C6H5)3Cl2]	F(000) = 832
Mr = 423.95	Dx = 1.691 Mg m^−3
Monoclinic, Pc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P -2yc	Cell parameters from 9955 reflections
a = 13.8005 (5) Å	θ = 2.6–28.4°
b = 10.0348 (3) Å	µ = 1.97 mm^−1
c = 13.4973 (4) Å	T = 150 K
β = 117.008 (1)°	Triangular, black
V = 1665.33 (9) Å^3	0.11 × 0.10 × 0.06 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer	7897 independent reflections
Radiation source: fine-focus sealed tube	7687 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
ϕ and ω scans	θmax = 28.4°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −18→18
Tmin = 0.813, Tmax = 0.891	k = −13→13
27243 measured reflections	l = −17→17

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.016	H-atom parameters constrained
wR(F^2) = 0.037	w = 1/[σ^2(Fo^2) + (0.0158P)^2 + 0.2589P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.002
7897 reflections	Δρmax = 0.65 e Å^−3
307 parameters	Δρmin = −0.27 e Å^−3
2 restraints	Absolute structure: Flack (1983), with 3739 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.005 (9)

Special details

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. Refinement of F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > σ(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ 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
Sb1	0.516196 (10)	0.410466 (12)	0.360811 (11)	0.01967 (3)
Cl1	0.47182 (5)	0.62724 (5)	0.41898 (5)	0.02844 (11)
Cl2	0.56490 (4)	0.19472 (5)	0.30340 (4)	0.02648 (11)
C11	0.52453 (12)	0.32053 (14)	0.50509 (10)	0.0286 (5)
C12	0.61431 (11)	0.24424 (17)	0.57322 (13)	0.0407 (6)
H12A	0.6724	0.2324	0.5546	0.049*
C13	0.61910 (15)	0.18534 (17)	0.66855 (12)	0.0594 (9)
H13A	0.6805	0.1332	0.7151	0.071*
C14	0.53412 (18)	0.20273 (17)	0.69576 (12)	0.0646 (10)
H14A	0.5374	0.1625	0.7609	0.078*
C15	0.44433 (15)	0.27902 (18)	0.62763 (15)	0.0511 (8)
H15A	0.3862	0.2909	0.6462	0.061*
C16	0.43954 (11)	0.33793 (15)	0.53230 (13)	0.0352 (5)
H16A	0.3782	0.3901	0.4857	0.042*
C21	0.65599 (10)	0.49606 (14)	0.36083 (12)	0.0255 (4)
C22	0.72186 (12)	0.58044 (15)	0.44681 (11)	0.0355 (5)
H22A	0.7040	0.5995	0.5055	0.043*
C23	0.81388 (11)	0.63690 (15)	0.44693 (13)	0.0477 (7)
H23A	0.8589	0.6946	0.5057	0.057*
C24	0.84004 (11)	0.60898 (16)	0.36106 (16)	0.0477 (7)
H24A	0.9029	0.6476	0.3611	0.057*
C25	0.77417 (12)	0.52460 (16)	0.27507 (13)	0.0399 (6)
H25A	0.7920	0.5055	0.2164	0.048*
C26	0.68215 (11)	0.46813 (14)	0.27496 (11)	0.0288 (5)
H26A	0.6371	0.4105	0.2162	0.035*
C31	0.36571 (8)	0.41118 (14)	0.21673 (9)	0.0212 (4)
C32	0.27217 (11)	0.45237 (15)	0.22235 (9)	0.0294 (5)
H32A	0.2762	0.4809	0.2912	0.035*
C33	0.17273 (8)	0.45184 (16)	0.12718 (12)	0.0345 (5)
H33A	0.1088	0.4800	0.1310	0.041*
C34	0.16685 (9)	0.41012 (16)	0.02639 (10)	0.0344 (5)
H34A	0.0989	0.4098	−0.0386	0.041*
C35	0.26039 (11)	0.36893 (16)	0.02077 (9)	0.0344 (5)
H35A	0.2564	0.3404	−0.0481	0.041*
C36	0.35982 (9)	0.36946 (15)	0.11594 (11)	0.0266 (5)
H36A	0.4238	0.3413	0.1121	0.032*
Sb2	0.026614 (10)	0.132484 (11)	0.368407 (10)	0.01849 (3)
Cl3	0.01239 (5)	−0.09218 (5)	0.43701 (5)	0.02921 (12)
Cl4	0.03114 (5)	0.35913 (5)	0.29907 (5)	0.02905 (11)
C41	0.02902 (11)	0.21206 (14)	0.51325 (9)	0.0227 (4)
C42	0.11621 (10)	0.17867 (15)	0.61440 (11)	0.0341 (5)
H42A	0.1743	0.1265	0.6159	0.041*
C43	0.11840 (13)	0.22166 (17)	0.71330 (9)	0.0443 (7)
H43A	0.1780	0.1988	0.7824	0.053*
C44	0.03340 (15)	0.29803 (17)	0.71105 (10)	0.0442 (7)
H44A	0.0349	0.3274	0.7786	0.053*
C45	−0.05380 (12)	0.33143 (16)	0.60990 (13)	0.0402 (6)
H45A	−0.1119	0.3836	0.6084	0.048*
C46	−0.05599 (10)	0.28844 (15)	0.51100 (10)	0.0303 (5)
H46A	−0.1156	0.3113	0.4419	0.036*
C51	−0.11737 (9)	0.09950 (15)	0.22231 (9)	0.0222 (4)
C52	−0.21676 (11)	0.14509 (15)	0.21167 (10)	0.0292 (5)
H52A	−0.2208	0.1867	0.2729	0.035*
C53	−0.31021 (8)	0.12974 (16)	0.11146 (12)	0.0328 (5)
H53A	−0.3781	0.1609	0.1042	0.039*
C54	−0.30427 (9)	0.06880 (16)	0.02189 (9)	0.0317 (5)
H54A	−0.3681	0.0583	−0.0466	0.038*
C55	−0.20489 (11)	0.02321 (16)	0.03253 (10)	0.0358 (5)
H55A	−0.2008	−0.0184	−0.0287	0.043*
C56	−0.11144 (9)	0.03856 (16)	0.13274 (11)	0.0315 (5)
H56A	−0.0435	0.0074	0.1400	0.038*
C61	0.17630 (9)	0.08154 (14)	0.37188 (12)	0.0227 (4)
C62	0.20057 (11)	0.12758 (13)	0.28858 (11)	0.0287 (5)
H62A	0.1502	0.1827	0.2310	0.034*
C63	0.29855 (12)	0.09303 (15)	0.28957 (13)	0.0385 (6)
H63A	0.3151	0.1245	0.2326	0.046*
C64	0.37225 (10)	0.01243 (16)	0.37387 (15)	0.0448 (7)
H64A	0.4392	−0.0112	0.3745	0.054*
C65	0.34797 (10)	−0.03361 (15)	0.45718 (13)	0.0404 (6)
H65A	0.3983	−0.0887	0.5148	0.049*
C66	0.25000 (11)	0.00094 (14)	0.45618 (10)	0.0300 (5)
H66A	0.2334	−0.0305	0.5131	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb1	0.02246 (6)	0.01984 (6)	0.01900 (6)	0.00084 (7)	0.01141 (5)	−0.00125 (7)
Cl1	0.0395 (3)	0.0222 (3)	0.0313 (3)	0.0018 (2)	0.0228 (3)	−0.0037 (2)
Cl2	0.0320 (3)	0.0213 (2)	0.0332 (3)	0.0022 (2)	0.0210 (2)	−0.0023 (2)
C11	0.0455 (13)	0.0199 (10)	0.0210 (10)	−0.0007 (9)	0.0156 (10)	−0.0025 (8)
C12	0.0571 (16)	0.0305 (13)	0.0243 (12)	0.0084 (11)	0.0097 (11)	−0.0006 (10)
C13	0.104 (3)	0.0310 (14)	0.0255 (13)	0.0117 (16)	0.0136 (15)	0.0037 (11)
C14	0.139 (3)	0.0298 (15)	0.0332 (15)	−0.0028 (17)	0.0467 (19)	0.0006 (11)
C15	0.098 (2)	0.0318 (14)	0.0474 (16)	−0.0069 (15)	0.0536 (17)	−0.0030 (12)
C16	0.0572 (15)	0.0271 (12)	0.0331 (13)	−0.0006 (11)	0.0308 (12)	−0.0011 (10)
C21	0.0214 (9)	0.0221 (10)	0.0306 (11)	0.0003 (8)	0.0098 (9)	0.0007 (8)
C22	0.0311 (11)	0.0299 (13)	0.0414 (14)	0.0008 (9)	0.0130 (11)	−0.0081 (10)
C23	0.0270 (12)	0.0320 (14)	0.070 (2)	−0.0056 (10)	0.0103 (13)	−0.0136 (13)
C24	0.0295 (12)	0.0337 (14)	0.085 (2)	−0.0059 (10)	0.0302 (14)	−0.0021 (14)
C25	0.0340 (12)	0.0375 (14)	0.0605 (17)	0.0015 (10)	0.0321 (13)	0.0066 (12)
C26	0.0255 (10)	0.0285 (12)	0.0341 (12)	−0.0008 (9)	0.0148 (10)	0.0004 (9)
C31	0.0240 (10)	0.0195 (10)	0.0226 (10)	−0.0022 (7)	0.0127 (8)	0.0013 (8)
C32	0.0298 (11)	0.0314 (12)	0.0306 (12)	0.0052 (9)	0.0168 (10)	0.0014 (9)
C33	0.0263 (11)	0.0361 (13)	0.0394 (13)	0.0066 (9)	0.0135 (10)	0.0032 (11)
C34	0.0287 (11)	0.0318 (13)	0.0321 (13)	−0.0028 (9)	0.0046 (10)	0.0024 (10)
C35	0.0383 (13)	0.0384 (14)	0.0250 (12)	−0.0063 (10)	0.0130 (11)	−0.0031 (10)
C36	0.0284 (11)	0.0303 (12)	0.0238 (11)	−0.0045 (9)	0.0140 (9)	−0.0028 (9)
Sb2	0.02043 (6)	0.01877 (6)	0.01842 (6)	−0.00017 (6)	0.01069 (5)	−0.00083 (7)
Cl3	0.0392 (3)	0.0208 (2)	0.0340 (3)	−0.0029 (2)	0.0221 (3)	0.0013 (2)
Cl4	0.0402 (3)	0.0205 (2)	0.0306 (3)	0.0004 (2)	0.0197 (2)	0.0031 (2)
C41	0.0320 (10)	0.0184 (10)	0.0209 (10)	−0.0025 (8)	0.0147 (9)	−0.0010 (7)
C42	0.0452 (13)	0.0279 (12)	0.0245 (11)	0.0077 (10)	0.0115 (10)	−0.0003 (9)
C43	0.0721 (19)	0.0304 (13)	0.0198 (11)	0.0062 (12)	0.0115 (12)	0.0006 (9)
C44	0.086 (2)	0.0293 (13)	0.0300 (13)	−0.0072 (13)	0.0370 (14)	−0.0046 (10)
C45	0.0518 (15)	0.0394 (14)	0.0450 (15)	−0.0022 (12)	0.0355 (13)	−0.0102 (12)
C46	0.0320 (11)	0.0343 (13)	0.0271 (11)	0.0029 (9)	0.0156 (10)	−0.0039 (9)
C51	0.0226 (10)	0.0242 (11)	0.0203 (10)	−0.0009 (8)	0.0102 (8)	0.0007 (8)
C52	0.0263 (11)	0.0335 (12)	0.0308 (12)	−0.0014 (9)	0.0154 (10)	−0.0073 (10)
C53	0.0218 (10)	0.0358 (13)	0.0385 (13)	0.0022 (9)	0.0117 (10)	−0.0008 (10)
C54	0.0291 (11)	0.0320 (12)	0.0278 (12)	−0.0055 (9)	0.0076 (10)	−0.0009 (9)
C55	0.0370 (12)	0.0449 (15)	0.0256 (11)	−0.0029 (11)	0.0143 (10)	−0.0096 (10)
C56	0.0260 (10)	0.0416 (14)	0.0280 (12)	0.0033 (9)	0.0132 (9)	−0.0055 (10)
C61	0.0214 (9)	0.0202 (10)	0.0284 (11)	−0.0026 (7)	0.0128 (9)	−0.0063 (8)
C62	0.0312 (11)	0.0244 (11)	0.0351 (12)	−0.0053 (8)	0.0190 (10)	−0.0041 (9)
C63	0.0428 (14)	0.0302 (13)	0.0626 (18)	−0.0100 (10)	0.0414 (14)	−0.0104 (11)
C64	0.0271 (12)	0.0370 (14)	0.079 (2)	−0.0035 (10)	0.0314 (13)	−0.0106 (13)
C65	0.0263 (11)	0.0332 (13)	0.0562 (16)	0.0025 (10)	0.0138 (11)	−0.0024 (12)
C66	0.0262 (10)	0.0280 (11)	0.0330 (12)	−0.0003 (8)	0.0110 (10)	−0.0023 (9)

Geometric parameters (Å, º)

Sb1—C11	2.1016 (11)	Sb2—C51	2.0947 (12)
Sb1—C31	2.1040 (11)	Sb2—C41	2.0981 (12)
Sb1—C21	2.1116 (10)	Sb2—C61	2.1077 (15)
Sb1—Cl1	2.4820 (5)	Sb2—Cl4	2.4709 (5)
Sb1—Cl2	2.4925 (5)	Sb2—Cl3	2.4787 (5)
C11—C12	1.3900	C41—C42	1.3900
C11—C16	1.3900	C41—C46	1.3900
C12—C13	1.3900	C42—C43	1.3900
C12—H12A	0.9500	C42—H42A	0.9500
C13—C14	1.3900	C43—C44	1.3900
C13—H13A	0.9500	C43—H43A	0.9500
C14—C15	1.3900	C44—C45	1.3900
C14—H14A	0.9500	C44—H44A	0.9500
C15—C16	1.3900	C45—C46	1.3900
C15—H15A	0.9500	C45—H45A	0.9500
C16—H16A	0.9500	C46—H46A	0.9500
C21—C22	1.3900	C51—C52	1.3900
C21—C26	1.3900	C51—C56	1.3900
C22—C23	1.3900	C52—C53	1.3900
C22—H22A	0.9500	C52—H52A	0.9500
C23—C24	1.3900	C53—C54	1.3900
C23—H23A	0.9500	C53—H53A	0.9500
C24—C25	1.3900	C54—C55	1.3900
C24—H24A	0.9500	C54—H54A	0.9500
C25—C26	1.3900	C55—C56	1.3900
C25—H25A	0.9500	C55—H55A	0.9500
C26—H26A	0.9500	C56—H56A	0.9500
C31—C32	1.3900	C61—C62	1.3900
C31—C36	1.3900	C61—C66	1.3900
C32—C33	1.3900	C62—C63	1.3900
C32—H32A	0.9500	C62—H62A	0.9500
C33—C34	1.3900	C63—C64	1.3900
C33—H33A	0.9500	C63—H63A	0.9500
C34—C35	1.3900	C64—C65	1.3900
C34—H34A	0.9500	C64—H64A	0.9500
C35—C36	1.3900	C65—C66	1.3900
C35—H35A	0.9500	C65—H65A	0.9500
C36—H36A	0.9500	C66—H66A	0.9500
C11—Sb1—C31	118.27 (6)	C51—Sb2—C41	122.97 (5)
C11—Sb1—C21	120.60 (6)	C51—Sb2—C61	118.93 (5)
C31—Sb1—C21	121.13 (6)	C41—Sb2—C61	118.10 (5)
C11—Sb1—Cl1	90.04 (4)	C51—Sb2—Cl4	88.01 (4)
C31—Sb1—Cl1	90.44 (4)	C41—Sb2—Cl4	90.58 (4)
C21—Sb1—Cl1	90.01 (4)	C61—Sb2—Cl4	92.21 (4)
C11—Sb1—Cl2	90.35 (4)	C51—Sb2—Cl3	90.33 (5)
C31—Sb1—Cl2	90.46 (4)	C41—Sb2—Cl3	88.19 (4)
C21—Sb1—Cl2	88.74 (4)	C61—Sb2—Cl3	90.81 (4)
Cl1—Sb1—Cl2	178.716 (19)	Cl4—Sb2—Cl3	176.97 (2)
C12—C11—C16	120.0	C42—C41—C46	120.0
C12—C11—Sb1	120.45 (8)	C42—C41—Sb2	117.63 (7)
C16—C11—Sb1	119.55 (8)	C46—C41—Sb2	122.24 (7)
C13—C12—C11	120.0	C43—C42—C41	120.0
C13—C12—H12A	120.0	C43—C42—H42A	120.0
C11—C12—H12A	120.0	C41—C42—H42A	120.0
C14—C13—C12	120.0	C42—C43—C44	120.0
C14—C13—H13A	120.0	C42—C43—H43A	120.0
C12—C13—H13A	120.0	C44—C43—H43A	120.0
C13—C14—C15	120.0	C45—C44—C43	120.0
C13—C14—H14A	120.0	C45—C44—H44A	120.0
C15—C14—H14A	120.0	C43—C44—H44A	120.0
C14—C15—C16	120.0	C46—C45—C44	120.0
C14—C15—H15A	120.0	C46—C45—H45A	120.0
C16—C15—H15A	120.0	C44—C45—H45A	120.0
C15—C16—C11	120.0	C45—C46—C41	120.0
C15—C16—H16A	120.0	C45—C46—H46A	120.0
C11—C16—H16A	120.0	C41—C46—H46A	120.0
C22—C21—C26	120.0	C52—C51—C56	120.0
C22—C21—Sb1	119.93 (7)	C52—C51—Sb2	120.99 (7)
C26—C21—Sb1	120.07 (7)	C56—C51—Sb2	118.88 (7)
C23—C22—C21	120.0	C51—C52—C53	120.0
C23—C22—H22A	120.0	C51—C52—H52A	120.0
C21—C22—H22A	120.0	C53—C52—H52A	120.0
C22—C23—C24	120.0	C54—C53—C52	120.0
C22—C23—H23A	120.0	C54—C53—H53A	120.0
C24—C23—H23A	120.0	C52—C53—H53A	120.0
C23—C24—C25	120.0	C53—C54—C55	120.0
C23—C24—H24A	120.0	C53—C54—H54A	120.0
C25—C24—H24A	120.0	C55—C54—H54A	120.0
C26—C25—C24	120.0	C56—C55—C54	120.0
C26—C25—H25A	120.0	C56—C55—H55A	120.0
C24—C25—H25A	120.0	C54—C55—H55A	120.0
C25—C26—C21	120.0	C55—C56—C51	120.0
C25—C26—H26A	120.0	C55—C56—H56A	120.0
C21—C26—H26A	120.0	C51—C56—H56A	120.0
C32—C31—C36	120.0	C62—C61—C66	120.0
C32—C31—Sb1	120.13 (7)	C62—C61—Sb2	119.68 (7)
C36—C31—Sb1	119.87 (7)	C66—C61—Sb2	120.31 (7)
C33—C32—C31	120.0	C61—C62—C63	120.0
C33—C32—H32A	120.0	C61—C62—H62A	120.0
C31—C32—H32A	120.0	C63—C62—H62A	120.0
C34—C33—C32	120.0	C62—C63—C64	120.0
C34—C33—H33A	120.0	C62—C63—H63A	120.0
C32—C33—H33A	120.0	C64—C63—H63A	120.0
C33—C34—C35	120.0	C63—C64—C65	120.0
C33—C34—H34A	120.0	C63—C64—H64A	120.0
C35—C34—H34A	120.0	C65—C64—H64A	120.0
C36—C35—C34	120.0	C64—C65—C66	120.0
C36—C35—H35A	120.0	C64—C65—H65A	120.0
C34—C35—H35A	120.0	C66—C65—H65A	120.0
C35—C36—C31	120.0	C65—C66—C61	120.0
C35—C36—H36A	120.0	C65—C66—H66A	120.0
C31—C36—H36A	120.0	C61—C66—H66A	120.0
C31—Sb1—C11—C12	140.10 (8)	C51—Sb2—C41—C42	152.98 (8)
C21—Sb1—C11—C12	−39.34 (10)	C61—Sb2—C41—C42	−26.19 (10)
Cl1—Sb1—C11—C12	−129.38 (8)	Cl4—Sb2—C41—C42	−119.01 (8)
Cl2—Sb1—C11—C12	49.40 (8)	Cl3—Sb2—C41—C42	63.76 (8)
C31—Sb1—C11—C16	−39.99 (10)	C51—Sb2—C41—C46	−22.82 (11)
C21—Sb1—C11—C16	140.56 (9)	C61—Sb2—C41—C46	158.00 (8)
Cl1—Sb1—C11—C16	50.53 (8)	Cl4—Sb2—C41—C46	65.18 (8)
Cl2—Sb1—C11—C16	−130.70 (8)	Cl3—Sb2—C41—C46	−112.04 (8)
C16—C11—C12—C13	0.0	C46—C41—C42—C43	0.0
Sb1—C11—C12—C13	179.91 (11)	Sb2—C41—C42—C43	−175.90 (10)
C11—C12—C13—C14	0.0	C41—C42—C43—C44	0.0
C12—C13—C14—C15	0.0	C42—C43—C44—C45	0.0
C13—C14—C15—C16	0.0	C43—C44—C45—C46	0.0
C14—C15—C16—C11	0.0	C44—C45—C46—C41	0.0
C12—C11—C16—C15	0.0	C42—C41—C46—C45	0.0
Sb1—C11—C16—C15	−179.91 (11)	Sb2—C41—C46—C45	175.71 (11)
C11—Sb1—C21—C22	−47.30 (10)	C41—Sb2—C51—C52	8.18 (11)
C31—Sb1—C21—C22	133.27 (8)	C61—Sb2—C51—C52	−172.65 (8)
Cl1—Sb1—C21—C22	42.75 (8)	Cl4—Sb2—C51—C52	−81.23 (8)
Cl2—Sb1—C21—C22	−136.96 (8)	Cl3—Sb2—C51—C52	96.24 (8)
C11—Sb1—C21—C26	132.72 (8)	C41—Sb2—C51—C56	−175.97 (8)
C31—Sb1—C21—C26	−46.71 (10)	C61—Sb2—C51—C56	3.21 (10)
Cl1—Sb1—C21—C26	−137.22 (8)	Cl4—Sb2—C51—C56	94.63 (8)
Cl2—Sb1—C21—C26	43.06 (8)	Cl3—Sb2—C51—C56	−87.90 (8)
C26—C21—C22—C23	0.0	C56—C51—C52—C53	0.0
Sb1—C21—C22—C23	−179.98 (11)	Sb2—C51—C52—C53	175.81 (11)
C21—C22—C23—C24	0.0	C51—C52—C53—C54	0.0
C22—C23—C24—C25	0.0	C52—C53—C54—C55	0.0
C23—C24—C25—C26	0.0	C53—C54—C55—C56	0.0
C24—C25—C26—C21	0.0	C54—C55—C56—C51	0.0
C22—C21—C26—C25	0.0	C52—C51—C56—C55	0.0
Sb1—C21—C26—C25	179.98 (11)	Sb2—C51—C56—C55	−175.90 (10)
C11—Sb1—C31—C32	49.05 (10)	C51—Sb2—C61—C62	51.39 (10)
C21—Sb1—C31—C32	−131.51 (8)	C41—Sb2—C61—C62	−129.40 (8)
Cl1—Sb1—C31—C32	−41.23 (8)	Cl4—Sb2—C61—C62	−37.55 (7)
Cl2—Sb1—C31—C32	139.69 (7)	Cl3—Sb2—C61—C62	142.22 (7)
C11—Sb1—C31—C36	−130.50 (8)	C51—Sb2—C61—C66	−127.81 (8)
C21—Sb1—C31—C36	48.95 (10)	C41—Sb2—C61—C66	51.40 (10)
Cl1—Sb1—C31—C36	139.22 (8)	Cl4—Sb2—C61—C66	143.25 (7)
Cl2—Sb1—C31—C36	−39.86 (8)	Cl3—Sb2—C61—C66	−36.98 (7)
C36—C31—C32—C33	0.0	C66—C61—C62—C63	0.0
Sb1—C31—C32—C33	−179.54 (10)	Sb2—C61—C62—C63	−179.20 (10)
C31—C32—C33—C34	0.0	C61—C62—C63—C64	0.0
C32—C33—C34—C35	0.0	C62—C63—C64—C65	0.0
C33—C34—C35—C36	0.0	C63—C64—C65—C66	0.0
C34—C35—C36—C31	0.0	C64—C65—C66—C61	0.0
C32—C31—C36—C35	0.0	C62—C61—C66—C65	0.0
Sb1—C31—C36—C35	179.55 (10)	Sb2—C61—C66—C65	179.20 (10)