Buy article online - an online subscription or single-article purchase is required to access this article.
The redetermination of the structure of the title compound, C12H22Si2, agrees with the results previously reported by Menczel & Kiss [Acta Cryst. (1975). B31, 1787-1789], but with improved precision. The molecules are located on centres of inversion. As a result, there is just a half molecule in the asymmetric unit.
Supporting information
CCDC reference: 183805
Key indicators
- Single-crystal X-ray study
- T = 173 K
- Mean (C-C) = 0.002 Å
- R factor = 0.038
- wR factor = 0.092
- Data-to-parameter ratio = 30.5
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991).
p-Bis(trimethylsilyl)benzene
top
Crystal data top
C12H22Si2 | F(000) = 244 |
Mr = 222.48 | Dx = 1.036 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 6.5410 (7) Å | Cell parameters from 11837 reflections |
b = 10.5452 (10) Å | θ = 3.6–29.6° |
c = 10.3952 (12) Å | µ = 0.22 mm−1 |
β = 96.029 (9)° | T = 173 K |
V = 713.05 (13) Å3 | Block, colourless |
Z = 2 | 0.39 × 0.19 × 0.17 mm |
Data collection top
Stoe IPDS II two-circle diffractometer | 1955 independent reflections |
Radiation source: fine-focus sealed tube | 1739 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.044 |
ω scans | θmax = 29.4°, θmin = 3.7° |
Absorption correction: empirical (using intensity measurements) (MULABS; Spek, 1990; Blessing, 1995) | h = −9→8 |
Tmin = 0.920, Tmax = 0.964 | k = −14→14 |
9295 measured reflections | l = −14→14 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.038 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.092 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0421P)2 + 0.2264P] where P = (Fo2 + 2Fc2)/3 |
1955 reflections | (Δ/σ)max < 0.001 |
64 parameters | Δρmax = 0.34 e Å−3 |
0 restraints | Δρmin = −0.21 e Å−3 |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
Si1 | 0.61753 (5) | 0.71754 (3) | 0.72548 (3) | 0.02454 (11) | |
C1 | 0.55416 (18) | 0.59355 (11) | 0.59730 (11) | 0.0218 (2) | |
C2 | 0.69981 (19) | 0.54436 (12) | 0.52133 (12) | 0.0243 (2) | |
H2 | 0.8377 | 0.5737 | 0.5346 | 0.029* | |
C3 | 0.64670 (19) | 0.45318 (12) | 0.42652 (12) | 0.0249 (2) | |
H3 | 0.7496 | 0.4219 | 0.3767 | 0.030* | |
C4 | 0.4851 (3) | 0.86872 (16) | 0.67299 (19) | 0.0470 (4) | |
H4A | 0.5349 | 0.8981 | 0.5924 | 0.071* | |
H4B | 0.5145 | 0.9332 | 0.7403 | 0.071* | |
H4C | 0.3365 | 0.8542 | 0.6587 | 0.071* | |
C5 | 0.9003 (2) | 0.74497 (16) | 0.75101 (15) | 0.0361 (3) | |
H5A | 0.9488 | 0.7745 | 0.6702 | 0.054* | |
H5B | 0.9700 | 0.6656 | 0.7779 | 0.054* | |
H5C | 0.9307 | 0.8093 | 0.8184 | 0.054* | |
C6 | 0.5229 (3) | 0.6619 (2) | 0.87860 (15) | 0.0453 (4) | |
H6A | 0.3742 | 0.6479 | 0.8645 | 0.068* | |
H6B | 0.5531 | 0.7261 | 0.9460 | 0.068* | |
H6C | 0.5918 | 0.5823 | 0.9059 | 0.068* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Si1 | 0.02515 (18) | 0.02445 (18) | 0.02354 (17) | −0.00041 (13) | 0.00030 (12) | −0.00650 (13) |
C1 | 0.0243 (5) | 0.0202 (5) | 0.0204 (5) | −0.0003 (4) | 0.0002 (4) | −0.0015 (4) |
C2 | 0.0207 (5) | 0.0259 (6) | 0.0259 (6) | −0.0026 (4) | 0.0009 (4) | −0.0039 (4) |
C3 | 0.0234 (6) | 0.0268 (6) | 0.0250 (6) | −0.0005 (4) | 0.0047 (4) | −0.0050 (4) |
C4 | 0.0524 (10) | 0.0293 (7) | 0.0562 (10) | 0.0070 (7) | −0.0092 (8) | −0.0095 (7) |
C5 | 0.0309 (7) | 0.0389 (8) | 0.0382 (7) | −0.0053 (5) | 0.0013 (6) | −0.0151 (6) |
C6 | 0.0476 (9) | 0.0618 (11) | 0.0273 (7) | −0.0096 (8) | 0.0080 (6) | −0.0083 (7) |
Geometric parameters (Å, º) top
Si1—C6 | 1.8622 (17) | C4—H4A | 0.9800 |
Si1—C5 | 1.8633 (15) | C4—H4B | 0.9800 |
Si1—C4 | 1.8683 (17) | C4—H4C | 0.9800 |
Si1—C1 | 1.8817 (12) | C5—H5A | 0.9800 |
C1—C2 | 1.3994 (17) | C5—H5B | 0.9800 |
C1—C3i | 1.4007 (17) | C5—H5C | 0.9800 |
C2—C3 | 1.3946 (17) | C6—H6A | 0.9800 |
C2—H2 | 0.9500 | C6—H6B | 0.9800 |
C3—C1i | 1.4007 (17) | C6—H6C | 0.9800 |
C3—H3 | 0.9500 | | |
| | | |
C6—Si1—C5 | 109.95 (8) | H4A—C4—H4B | 109.5 |
C6—Si1—C4 | 109.47 (10) | Si1—C4—H4C | 109.5 |
C5—Si1—C4 | 109.39 (8) | H4A—C4—H4C | 109.5 |
C6—Si1—C1 | 108.53 (7) | H4B—C4—H4C | 109.5 |
C5—Si1—C1 | 110.51 (6) | Si1—C5—H5A | 109.5 |
C4—Si1—C1 | 108.98 (7) | Si1—C5—H5B | 109.5 |
C2—C1—C3i | 116.83 (11) | H5A—C5—H5B | 109.5 |
C2—C1—Si1 | 123.01 (9) | Si1—C5—H5C | 109.5 |
C3i—C1—Si1 | 120.16 (9) | H5A—C5—H5C | 109.5 |
C3—C2—C1 | 121.37 (11) | H5B—C5—H5C | 109.5 |
C3—C2—H2 | 119.3 | Si1—C6—H6A | 109.5 |
C1—C2—H2 | 119.3 | Si1—C6—H6B | 109.5 |
C2—C3—C1i | 121.80 (11) | H6A—C6—H6B | 109.5 |
C2—C3—H3 | 119.1 | Si1—C6—H6C | 109.5 |
C1i—C3—H3 | 119.1 | H6A—C6—H6C | 109.5 |
Si1—C4—H4A | 109.5 | H6B—C6—H6C | 109.5 |
Si1—C4—H4B | 109.5 | | |
| | | |
C6—Si1—C1—C2 | −128.90 (12) | C4—Si1—C1—C3i | −67.55 (13) |
C5—Si1—C1—C2 | −8.26 (13) | C3i—C1—C2—C3 | 0.0 (2) |
C4—Si1—C1—C2 | 111.96 (12) | Si1—C1—C2—C3 | −179.51 (10) |
C6—Si1—C1—C3i | 51.60 (13) | C1—C2—C3—C1i | 0.0 (2) |
C5—Si1—C1—C3i | 172.23 (11) | | |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Subscribe to Acta Crystallographica Section E: Crystallographic Communications
The full text of this article is available to subscribers to the journal.
If you have already registered and are using a computer listed in your registration details, please email
support@iucr.org for assistance.