ortho-Bis(dimethyl­silyl)hexa­methyl­deca­silasesquioxane

The title compound, C₁₀H₃₀O₁₁Si₈, crystallizes with two half-mol­ecules in the asymmetric unit; each molecule is located on a twofold rotation axis. The geometric parameters of the two crystallographically independent mol­ecules are almost identical.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](i-C) = 0.005 Å
• R factor = 0.070
• wR factor = 0.163
• Data-to-parameter ratio = 23.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         O3
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.12 Ratio

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Siemens,1995); cell refinement: SMART; data reduction: SAINT (Siemens,1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Sheldrick, 1991); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

ortho-Bis(dimethylsilyl)hexamethyldecasilasesquioxane

Crystal data

C10H30O11Si8	F(000) = 2320
Mr = 551.06	Dx = 1.398 Mg m^−3
Orthorhombic, Pnna	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2a 2bc	Cell parameters from 510 reflections
a = 16.927 (1) Å	θ = 1–25°
b = 36.212 (2) Å	µ = 0.45 mm^−1
c = 8.5413 (7) Å	T = 173 K
V = 5235.5 (6) Å^3	Needle, colourless
Z = 8	0.52 × 0.18 × 0.15 mm

Data collection

Siemens CCD three-circle diffractometer	6239 independent reflections
Radiation source: fine-focus sealed tube	4682 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.096
ω scans	θmax = 27.9°, θmin = 1.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −22→21
Tmin = 0.798, Tmax = 0.935	k = −47→46
85682 measured reflections	l = −11→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.070	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.163	H-atom parameters constrained
S = 1.25	w = 1/[σ^2(Fo^2) + (0.0317P)^2 + 21.419P] where P = (Fo^2 + 2Fc^2)/3
6239 reflections	(Δ/σ)max = 0.001
263 parameters	Δρmax = 0.59 e Å^−3
0 restraints	Δρmin = −0.43 e Å^−3

Special details

Experimental. ;

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
Si1	0.18840 (7)	0.55532 (3)	0.42429 (15)	0.0227 (3)
O1	0.1461 (2)	0.57743 (9)	0.2815 (4)	0.0319 (8)
Si2	0.14363 (8)	0.58331 (3)	0.09192 (16)	0.0275 (3)
O2	0.1287 (2)	0.54299 (8)	0.0084 (4)	0.0324 (8)
Si3	0.15774 (8)	0.50070 (4)	−0.01006 (16)	0.0255 (3)
O3	0.1484 (2)	0.47975 (9)	0.1564 (4)	0.0396 (9)
Si4	0.14363 (7)	0.47375 (3)	0.34383 (15)	0.0228 (3)
O4	0.15285 (19)	0.51340 (8)	0.4316 (4)	0.0299 (7)
C11	0.1700 (3)	0.57915 (14)	0.6100 (6)	0.0340 (12)
H11A	0.1960	0.5657	0.6953	0.051*
H11B	0.1130	0.5802	0.6296	0.051*
H11C	0.1912	0.6043	0.6044	0.051*
O11	0.28341 (19)	0.55317 (9)	0.3931 (4)	0.0318 (8)
C21	0.0583 (3)	0.61300 (14)	0.0403 (7)	0.0406 (13)
H21A	0.0568	0.6166	−0.0734	0.061*
H21B	0.0636	0.6370	0.0925	0.061*
H21C	0.0092	0.6011	0.0744	0.061*
C22	0.2389 (3)	0.60300 (13)	0.0281 (6)	0.0368 (12)
H22A	0.2381	0.6067	−0.0856	0.055*
H22B	0.2818	0.5860	0.0555	0.055*
H22C	0.2475	0.6268	0.0804	0.055*
C31	0.0987 (3)	0.47711 (15)	−0.1612 (7)	0.0415 (13)
H31A	0.1167	0.4515	−0.1716	0.062*
H31B	0.1051	0.4899	−0.2615	0.062*
H31C	0.0429	0.4774	−0.1308	0.062*
O31	0.2500	0.5000	−0.0627 (7)	0.0476 (14)
C41	0.0489 (3)	0.45220 (13)	0.3971 (7)	0.0377 (13)
H41A	0.0466	0.4488	0.5108	0.057*
H41B	0.0443	0.4282	0.3452	0.057*
H41C	0.0053	0.4682	0.3637	0.057*
Si5	0.17809 (7)	0.69483 (3)	0.37650 (15)	0.0202 (3)
O5	0.25270 (19)	0.67174 (9)	0.4444 (4)	0.0330 (8)
Si6	0.34846 (7)	0.66939 (3)	0.47189 (16)	0.0257 (3)
O6	0.38211 (19)	0.71130 (8)	0.5021 (4)	0.0282 (7)
Si7	0.39504 (7)	0.75260 (4)	0.43218 (16)	0.0260 (3)
O7	0.3125 (2)	0.77528 (9)	0.4400 (5)	0.0392 (9)
Si8	0.21684 (7)	0.77791 (3)	0.45787 (15)	0.0224 (3)
O8	0.17960 (19)	0.73660 (8)	0.4468 (4)	0.0278 (7)
C51	0.0861 (3)	0.67185 (12)	0.4371 (6)	0.0285 (10)
H51A	0.0407	0.6856	0.3962	0.043*
H51B	0.0833	0.6711	0.5517	0.043*
H51C	0.0851	0.6466	0.3958	0.043*
O51	0.18369 (19)	0.69704 (8)	0.1862 (4)	0.0273 (7)
C61	0.3675 (3)	0.64142 (15)	0.6488 (7)	0.0402 (13)
H61A	0.3478	0.6163	0.6324	0.060*
H61B	0.3403	0.6525	0.7386	0.060*
H61C	0.4244	0.6406	0.6693	0.060*
C62	0.3956 (3)	0.64913 (15)	0.2947 (7)	0.0408 (13)
H62A	0.3752	0.6241	0.2778	0.061*
H62B	0.4529	0.6481	0.3097	0.061*
H62C	0.3834	0.6645	0.2034	0.061*
C71	0.4700 (3)	0.77716 (14)	0.5474 (7)	0.0385 (13)
H71A	0.5201	0.7636	0.5427	0.058*
H71B	0.4525	0.7790	0.6565	0.058*
H71C	0.4774	0.8020	0.5045	0.058*
O71	0.4226 (3)	0.7500	0.2500	0.0419 (13)
C81	0.1878 (4)	0.79944 (14)	0.6445 (6)	0.0397 (13)
H81A	0.1300	0.8006	0.6510	0.060*
H81B	0.2095	0.8245	0.6500	0.060*
H81C	0.2083	0.7847	0.7317	0.060*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Si1	0.0242 (6)	0.0239 (6)	0.0201 (6)	−0.0002 (5)	0.0017 (5)	−0.0015 (5)
O1	0.0367 (19)	0.0354 (18)	0.0236 (18)	0.0073 (15)	−0.0029 (15)	0.0021 (14)
Si2	0.0340 (7)	0.0240 (6)	0.0247 (7)	0.0039 (5)	−0.0034 (6)	0.0002 (5)
O2	0.038 (2)	0.0259 (16)	0.0335 (19)	0.0030 (14)	−0.0057 (16)	−0.0010 (15)
Si3	0.0269 (6)	0.0262 (6)	0.0235 (6)	0.0013 (5)	−0.0028 (5)	−0.0014 (5)
O3	0.064 (3)	0.0330 (18)	0.0221 (18)	0.0017 (18)	−0.0013 (18)	−0.0004 (15)
Si4	0.0224 (6)	0.0232 (6)	0.0229 (7)	−0.0018 (5)	−0.0005 (5)	−0.0002 (5)
O4	0.0302 (18)	0.0257 (16)	0.0337 (19)	−0.0035 (14)	−0.0009 (15)	−0.0037 (14)
C11	0.037 (3)	0.035 (3)	0.029 (3)	−0.005 (2)	0.003 (2)	−0.008 (2)
O11	0.0244 (17)	0.0297 (17)	0.041 (2)	−0.0009 (14)	0.0071 (15)	−0.0010 (15)
C21	0.049 (3)	0.035 (3)	0.038 (3)	0.011 (2)	−0.005 (3)	0.002 (2)
C22	0.045 (3)	0.032 (3)	0.034 (3)	−0.003 (2)	0.000 (2)	0.002 (2)
C31	0.046 (3)	0.040 (3)	0.038 (3)	−0.004 (3)	−0.010 (3)	−0.007 (2)
O31	0.032 (3)	0.068 (4)	0.044 (3)	0.006 (3)	0.000	0.000
C41	0.028 (3)	0.027 (2)	0.058 (4)	−0.005 (2)	0.006 (2)	−0.002 (2)
Si5	0.0164 (6)	0.0216 (6)	0.0227 (6)	−0.0019 (5)	0.0001 (5)	0.0003 (5)
O5	0.0189 (16)	0.0342 (18)	0.046 (2)	−0.0016 (14)	−0.0039 (16)	0.0073 (16)
Si6	0.0187 (6)	0.0236 (6)	0.0348 (8)	0.0000 (5)	−0.0036 (5)	0.0054 (5)
O6	0.0282 (17)	0.0273 (16)	0.0293 (18)	−0.0029 (13)	−0.0045 (14)	0.0038 (14)
Si7	0.0201 (6)	0.0254 (6)	0.0325 (7)	−0.0030 (5)	−0.0053 (5)	0.0040 (5)
O7	0.0238 (17)	0.0288 (17)	0.065 (3)	−0.0004 (14)	−0.0062 (18)	0.0056 (17)
Si8	0.0236 (6)	0.0212 (6)	0.0223 (7)	−0.0002 (5)	−0.0025 (5)	−0.0014 (5)
O8	0.0269 (17)	0.0235 (15)	0.0329 (19)	−0.0043 (13)	0.0008 (15)	−0.0036 (14)
C51	0.019 (2)	0.029 (2)	0.037 (3)	−0.0031 (18)	−0.001 (2)	0.002 (2)
O51	0.0325 (18)	0.0260 (16)	0.0235 (17)	−0.0054 (14)	0.0004 (14)	−0.0013 (13)
C61	0.026 (3)	0.042 (3)	0.052 (4)	−0.004 (2)	−0.006 (2)	0.021 (3)
C62	0.038 (3)	0.036 (3)	0.048 (4)	0.004 (2)	−0.003 (3)	−0.006 (2)
C71	0.027 (3)	0.036 (3)	0.052 (4)	−0.005 (2)	−0.011 (2)	0.005 (2)
O71	0.045 (3)	0.048 (3)	0.032 (3)	0.000	0.000	0.009 (2)
C81	0.062 (4)	0.032 (3)	0.025 (3)	−0.002 (3)	−0.001 (3)	−0.002 (2)

Geometric parameters (Å, º)

Si1—O1	1.625 (3)	Si5—O5	1.622 (3)
Si1—O11	1.632 (3)	Si5—O8	1.628 (3)
Si1—O4	1.634 (3)	Si5—O51	1.630 (3)
Si1—C11	1.832 (5)	Si5—C51	1.841 (5)
O1—Si2	1.634 (3)	O5—Si6	1.640 (3)
Si2—O2	1.645 (3)	Si6—O6	1.642 (3)
Si2—C22	1.846 (5)	Si6—C61	1.848 (5)
Si2—C21	1.854 (5)	Si6—C62	1.861 (6)
O2—Si3	1.616 (3)	O6—Si7	1.625 (3)
Si3—O3	1.619 (4)	Si7—O7	1.622 (4)
Si3—O31	1.625 (2)	Si7—O71	1.627 (2)
Si3—C31	1.842 (5)	Si7—C71	1.835 (5)
O3—Si4	1.618 (4)	O7—Si8	1.629 (4)
Si4—O4	1.627 (3)	Si8—O8	1.626 (3)
Si4—O11^i	1.629 (3)	Si8—O51^ii	1.628 (3)
Si4—C41	1.841 (5)	Si8—C81	1.841 (5)
C11—H11A	0.9800	C51—H51A	0.9800
C11—H11B	0.9800	C51—H51B	0.9800
C11—H11C	0.9800	C51—H51C	0.9800
O11—Si4^i	1.629 (3)	O51—Si8^ii	1.628 (3)
C21—H21A	0.9800	C61—H61A	0.9800
C21—H21B	0.9800	C61—H61B	0.9800
C21—H21C	0.9800	C61—H61C	0.9800
C22—H22A	0.9800	C62—H62A	0.9800
C22—H22B	0.9800	C62—H62B	0.9800
C22—H22C	0.9800	C62—H62C	0.9800
C31—H31A	0.9800	C71—H71A	0.9800
C31—H31B	0.9800	C71—H71B	0.9800
C31—H31C	0.9800	C71—H71C	0.9800
O31—Si3^i	1.625 (2)	O71—Si7^ii	1.627 (2)
C41—H41A	0.9800	C81—H81A	0.9800
C41—H41B	0.9800	C81—H81B	0.9800
C41—H41C	0.9800	C81—H81C	0.9800
O1—Si1—O11	109.57 (19)	O5—Si5—O8	109.57 (18)
O1—Si1—O4	108.90 (19)	O5—Si5—O51	109.69 (19)
O11—Si1—O4	108.95 (18)	O8—Si5—O51	108.73 (18)
O1—Si1—C11	110.0 (2)	O5—Si5—C51	109.0 (2)
O11—Si1—C11	109.4 (2)	O8—Si5—C51	109.2 (2)
O4—Si1—C11	110.0 (2)	O51—Si5—C51	110.6 (2)
Si1—O1—Si2	145.0 (2)	Si5—O5—Si6	147.9 (2)
O1—Si2—O2	108.55 (19)	O5—Si6—O6	108.51 (17)
O1—Si2—C22	108.7 (2)	O5—Si6—C61	108.5 (2)
O2—Si2—C22	110.4 (2)	O6—Si6—C61	108.5 (2)
O1—Si2—C21	109.4 (2)	O5—Si6—C62	109.1 (2)
O2—Si2—C21	107.0 (2)	O6—Si6—C62	110.1 (2)
C22—Si2—C21	112.8 (2)	C61—Si6—C62	112.0 (3)
Si3—O2—Si2	146.8 (2)	Si7—O6—Si6	147.1 (2)
O2—Si3—O3	109.18 (19)	O7—Si7—O6	109.55 (18)
O2—Si3—O31	109.50 (15)	O7—Si7—O71	108.4 (2)
O3—Si3—O31	109.3 (2)	O6—Si7—O71	109.69 (15)
O2—Si3—C31	110.0 (2)	O7—Si7—C71	109.1 (2)
O3—Si3—C31	110.2 (2)	O6—Si7—C71	110.0 (2)
O31—Si3—C31	108.7 (3)	O71—Si7—C71	110.0 (3)
Si4—O3—Si3	159.5 (2)	Si7—O7—Si8	152.8 (2)
O3—Si4—O4	109.43 (19)	O8—Si8—O51^ii	109.55 (18)
O3—Si4—O11^i	107.4 (2)	O8—Si8—O7	109.02 (18)
O4—Si4—O11^i	109.67 (18)	O51^ii—Si8—O7	107.7 (2)
O3—Si4—C41	110.2 (3)	O8—Si8—C81	109.7 (2)
O4—Si4—C41	110.1 (2)	O51^ii—Si8—C81	109.0 (2)
O11^i—Si4—C41	110.1 (2)	O7—Si8—C81	111.8 (3)
Si4—O4—Si1	146.9 (2)	Si8—O8—Si5	152.0 (2)
Si1—C11—H11A	109.5	Si5—C51—H51A	109.5
Si1—C11—H11B	109.5	Si5—C51—H51B	109.5
H11A—C11—H11B	109.5	H51A—C51—H51B	109.5
Si1—C11—H11C	109.5	Si5—C51—H51C	109.5
H11A—C11—H11C	109.5	H51A—C51—H51C	109.5
H11B—C11—H11C	109.5	H51B—C51—H51C	109.5
Si4^i—O11—Si1	144.9 (2)	Si8^ii—O51—Si5	143.2 (2)
Si2—C21—H21A	109.5	Si6—C61—H61A	109.5
Si2—C21—H21B	109.5	Si6—C61—H61B	109.5
H21A—C21—H21B	109.5	H61A—C61—H61B	109.5
Si2—C21—H21C	109.5	Si6—C61—H61C	109.5
H21A—C21—H21C	109.5	H61A—C61—H61C	109.5
H21B—C21—H21C	109.5	H61B—C61—H61C	109.5
Si2—C22—H22A	109.5	Si6—C62—H62A	109.5
Si2—C22—H22B	109.5	Si6—C62—H62B	109.5
H22A—C22—H22B	109.5	H62A—C62—H62B	109.5
Si2—C22—H22C	109.5	Si6—C62—H62C	109.5
H22A—C22—H22C	109.5	H62A—C62—H62C	109.5
H22B—C22—H22C	109.5	H62B—C62—H62C	109.5
Si3—C31—H31A	109.5	Si7—C71—H71A	109.5
Si3—C31—H31B	109.5	Si7—C71—H71B	109.5
H31A—C31—H31B	109.5	H71A—C71—H71B	109.5
Si3—C31—H31C	109.5	Si7—C71—H71C	109.5
H31A—C31—H31C	109.5	H71A—C71—H71C	109.5
H31B—C31—H31C	109.5	H71B—C71—H71C	109.5
Si3—O31—Si3^i	147.9 (4)	Si7^ii—O71—Si7	146.7 (4)
Si4—C41—H41A	109.5	Si8—C81—H81A	109.5
Si4—C41—H41B	109.5	Si8—C81—H81B	109.5
H41A—C41—H41B	109.5	H81A—C81—H81B	109.5
Si4—C41—H41C	109.5	Si8—C81—H81C	109.5
H41A—C41—H41C	109.5	H81A—C81—H81C	109.5
H41B—C41—H41C	109.5	H81B—C81—H81C	109.5
O11—Si1—O1—Si2	41.4 (5)	O8—Si5—O5—Si6	−52.6 (5)
O4—Si1—O1—Si2	−77.6 (4)	O51—Si5—O5—Si6	66.7 (5)
C11—Si1—O1—Si2	161.7 (4)	C51—Si5—O5—Si6	−172.1 (5)
Si1—O1—Si2—O2	55.9 (5)	Si5—O5—Si6—O6	33.6 (5)
Si1—O1—Si2—C22	−64.3 (5)	Si5—O5—Si6—C61	151.3 (5)
Si1—O1—Si2—C21	172.2 (4)	Si5—O5—Si6—C62	−86.4 (5)
O1—Si2—O2—Si3	−54.5 (5)	O5—Si6—O6—Si7	−63.0 (5)
C22—Si2—O2—Si3	64.5 (5)	C61—Si6—O6—Si7	179.3 (4)
C21—Si2—O2—Si3	−172.4 (4)	C62—Si6—O6—Si7	56.4 (5)
Si2—O2—Si3—O3	64.2 (5)	Si6—O6—Si7—O7	78.1 (5)
Si2—O2—Si3—O31	−55.4 (5)	Si6—O6—Si7—O71	−40.8 (5)
Si2—O2—Si3—C31	−174.8 (4)	Si6—O6—Si7—C71	−161.9 (4)
O2—Si3—O3—Si4	−27.9 (9)	O6—Si7—O7—Si8	−16.7 (7)
O31—Si3—O3—Si4	91.8 (8)	O71—Si7—O7—Si8	102.9 (6)
C31—Si3—O3—Si4	−148.9 (8)	C71—Si7—O7—Si8	−137.2 (6)
Si3—O3—Si4—O4	1.6 (9)	Si7—O7—Si8—O8	−10.7 (7)
Si3—O3—Si4—O11^i	−117.3 (8)	Si7—O7—Si8—O51^ii	−129.5 (6)
Si3—O3—Si4—C41	122.8 (8)	Si7—O7—Si8—C81	110.7 (6)
O3—Si4—O4—Si1	−27.0 (5)	O51^ii—Si8—O8—Si5	82.0 (5)
O11^i—Si4—O4—Si1	90.5 (4)	O7—Si8—O8—Si5	−35.7 (5)
C41—Si4—O4—Si1	−148.2 (4)	C81—Si8—O8—Si5	−158.4 (5)
O1—Si1—O4—Si4	64.3 (5)	O5—Si5—O8—Si8	71.0 (5)
O11—Si1—O4—Si4	−55.2 (5)	O51—Si5—O8—Si8	−48.9 (5)
C11—Si1—O4—Si4	−175.1 (4)	C51—Si5—O8—Si8	−169.6 (5)
O1—Si1—O11—Si4^i	−107.3 (4)	O5—Si5—O51—Si8^ii	−92.0 (4)
O4—Si1—O11—Si4^i	11.7 (5)	O8—Si5—O51—Si8^ii	27.8 (4)
C11—Si1—O11—Si4^i	132.0 (4)	C51—Si5—O51—Si8^ii	147.8 (4)
O2—Si3—O31—Si3^i	89.67 (16)	O7—Si7—O71—Si7^ii	−32.01 (14)
O3—Si3—O31—Si3^i	−29.87 (14)	O6—Si7—O71—Si7^ii	87.58 (15)
C31—Si3—O31—Si3^i	−150.1 (2)	C71—Si7—O71—Si7^ii	−151.28 (19)

Symmetry codes: (i) −x+1/2, −y+1, z; (ii) x, −y+3/2, −z+1/2.