Tetra­kis(trimethyl­sil­yl)methane

The crystal structure of the title compound, C₁₃H₃₆Si₄, originally determined by powder diffraction methods, has been redetermined using single-crystal data. The mol­ecule is located on a threefold rotation axis with the methane C and one of the Si atoms located on this axis. All other atoms occupy general positions.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](i-C) = 0.011 Å
• R factor = 0.094
• wR factor = 0.237
• Data-to-parameter ratio = 12.8

checkCIF/PLATON results

No syntax errors found



Alert level A
DIFF020_ALERT_1_A  _diffrn_standards_interval_count and
            _diffrn_standards_interval_time are missing. Number of measurements
            between standards or time (min) between standards.
PLAT112_ALERT_2_A ADDSYM Detects Additional (Pseudo) Symm. Elem...         -4

Author Response: This is just pseudo symmetry.

PLAT112_ALERT_2_A ADDSYM Detects Additional (Pseudo) Symm. Elem...         -4

Author Response: This is just pseudo symmetry.

PLAT112_ALERT_2_A ADDSYM Detects Additional (Pseudo) Symm. Elem...         -4

Author Response: This is just pseudo symmetry.

PLAT112_ALERT_2_A ADDSYM Detects Additional (Pseudo) Symm. Elem...          m

Author Response: This is just pseudo symmetry.

PLAT112_ALERT_2_A ADDSYM Detects Additional (Pseudo) Symm. Elem...          m

Author Response: This is just pseudo symmetry.

PLAT112_ALERT_2_A ADDSYM Detects Additional (Pseudo) Symm. Elem...          m

Author Response: This is just pseudo symmetry.

PLAT113_ALERT_2_A ADDSYM Suggests Possible Pseudo/New Spacegroup .      F-43m

Author Response: The structure cannot be refined in this space group.

Alert level B
PLAT049_ALERT_1_B Calculated Density less than 1.0 gcm-3 .........       1.00

Alert level C
DIFMX01_ALERT_2_C  The maximum difference density is > 0.1*ZMAX*0.75
            _refine_diff_density_max given =      1.170
            Test value =      1.050
DIFMX02_ALERT_1_C  The minimum difference density is > 0.1*ZMAX*0.75
            The relevant atom site should be identified.
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.33
PLAT097_ALERT_2_C Maximum (Positive) Residual Density ............       1.17 e/A   3
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.12 Ratio
PLAT230_ALERT_2_C Hirshfeld Test Diff for    Si1    -   C1      ..       6.09 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    Si2    -   C1      ..       5.89 su
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C1
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.25 Ratio

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           25.09
           From the CIF: _reflns_number_total                679
           Count of symmetry unique reflns          689
           Completeness (_total/calc)             98.55%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present        yes

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

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
  14 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
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

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); software used to prepare material for publication: SHELXL97.

Tetrakis(trimethylsilyl)methane

Crystal data

C13H36Si4	Dx = 0.999 Mg m^−3
Mr = 304.78	Mo Kα radiation, λ = 0.71073 Å
Cubic, P213	Cell parameters from 13605 reflections
Hall symbol: P 2ac 2ab 3	θ = 2.7–25.1°
a = 12.6529 (10) Å	µ = 0.28 mm^−1
V = 2025.7 (3) Å^3	T = 173 K
Z = 4	Block, colourless
F(000) = 680	0.43 × 0.34 × 0.24 mm

Data collection

Stoe IPDS-II two-circle diffractometer	679 independent reflections
Radiation source: fine-focus sealed tube	670 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.073
ω scans	θmax = 25.1°, θmin = 3.2°
Absorption correction: multi-scan (MULABS; Spek, 2003; Blessing, 1995)	h = −14→14
Tmin = 0.890, Tmax = 0.936	k = −14→14
13605 measured reflections	l = −14→14

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)] = 0.094	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.237	H-atom parameters constrained
S = 1.18	w = 1/[σ^2(Fo^2) + (0.1815P)^2 + 1.6756P] where P = (Fo^2 + 2Fc^2)/3
679 reflections	(Δ/σ)max < 0.001
53 parameters	Δρmax = 1.17 e Å^−3
0 restraints	Δρmin = −0.50 e Å^−3

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
C1	0.0040 (6)	0.4960 (6)	0.5040 (6)	0.017 (2)
Si1	0.0920 (2)	0.4080 (2)	0.5920 (2)	0.0392 (12)
C11	0.0719 (10)	0.2601 (9)	0.5607 (12)	0.053 (3)
H11A	−0.0028	0.2417	0.5698	0.079*
H11B	0.1151	0.2175	0.6089	0.079*
H11C	0.0933	0.2461	0.4876	0.079*
Si2	0.0603 (2)	0.6370 (2)	0.5026 (2)	0.0361 (7)
C21	0.1766 (8)	0.6517 (10)	0.4084 (10)	0.046 (3)
H21A	0.1551	0.6297	0.3373	0.069*
H21B	0.2352	0.6072	0.4326	0.069*
H21C	0.1993	0.7257	0.4069	0.069*
C22	−0.0416 (10)	0.7390 (7)	0.4562 (9)	0.043 (2)
H22A	−0.0698	0.7178	0.3872	0.065*
H22B	−0.0078	0.8083	0.4500	0.065*
H22C	−0.0995	0.7429	0.5075	0.065*
C23	0.1119 (8)	0.6817 (9)	0.6369 (9)	0.045 (3)
H23A	0.0553	0.6760	0.6895	0.068*
H23B	0.1354	0.7554	0.6322	0.068*
H23C	0.1714	0.6368	0.6579	0.068*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.017 (2)	0.017 (2)	0.017 (2)	−0.001 (3)	0.001 (3)	−0.001 (3)
Si1	0.0392 (12)	0.0392 (12)	0.0392 (12)	0.0031 (11)	−0.0031 (11)	0.0031 (11)
C11	0.048 (6)	0.036 (6)	0.074 (8)	0.008 (5)	0.005 (6)	0.017 (6)
Si2	0.0388 (14)	0.0329 (14)	0.0364 (14)	−0.0047 (11)	0.0024 (14)	0.0002 (11)
C21	0.022 (4)	0.051 (6)	0.065 (6)	−0.009 (4)	0.011 (4)	0.012 (5)
C22	0.057 (7)	0.023 (4)	0.051 (6)	0.010 (4)	0.004 (5)	0.007 (4)
C23	0.036 (5)	0.053 (6)	0.047 (6)	−0.007 (5)	−0.010 (5)	−0.018 (5)

Geometric parameters (Å, º)

C1—Si2^i	1.921 (5)	Si2—C23	1.906 (11)
C1—Si2^ii	1.921 (5)	Si2—C22	1.917 (10)
C1—Si2	1.921 (5)	C21—H21A	0.9800
C1—Si1	1.928 (14)	C21—H21B	0.9800
Si1—C11^ii	1.930 (12)	C21—H21C	0.9800
Si1—C11^i	1.930 (12)	C22—H22A	0.9800
Si1—C11	1.930 (12)	C22—H22B	0.9800
C11—H11A	0.9800	C22—H22C	0.9800
C11—H11B	0.9800	C23—H23A	0.9800
C11—H11C	0.9800	C23—H23B	0.9800
Si2—C21	1.903 (11)	C23—H23C	0.9800
Si2^i—C1—Si2^ii	109.8 (4)	C21—Si2—C1	112.5 (4)
Si2^i—C1—Si2	109.8 (4)	C23—Si2—C1	113.3 (5)
Si2^ii—C1—Si2	109.8 (4)	C22—Si2—C1	112.2 (5)
Si2^i—C1—Si1	109.1 (4)	Si2—C21—H21A	109.5
Si2^ii—C1—Si1	109.1 (4)	Si2—C21—H21B	109.5
Si2—C1—Si1	109.1 (4)	H21A—C21—H21B	109.5
C11^ii—Si1—C11^i	107.4 (4)	Si2—C21—H21C	109.5
C11^ii—Si1—C11	107.4 (4)	H21A—C21—H21C	109.5
C11^i—Si1—C11	107.4 (4)	H21B—C21—H21C	109.5
C11^ii—Si1—C1	111.5 (4)	Si2—C22—H22A	109.5
C11^i—Si1—C1	111.5 (4)	Si2—C22—H22B	109.5
C11—Si1—C1	111.5 (4)	H22A—C22—H22B	109.5
Si1—C11—H11A	109.5	Si2—C22—H22C	109.5
Si1—C11—H11B	109.5	H22A—C22—H22C	109.5
H11A—C11—H11B	109.5	H22B—C22—H22C	109.5
Si1—C11—H11C	109.5	Si2—C23—H23A	109.5
H11A—C11—H11C	109.5	Si2—C23—H23B	109.5
H11B—C11—H11C	109.5	H23A—C23—H23B	109.5
C21—Si2—C23	105.3 (5)	Si2—C23—H23C	109.5
C21—Si2—C22	105.2 (6)	H23A—C23—H23C	109.5
C23—Si2—C22	107.7 (5)	H23B—C23—H23C	109.5
Si2^i—C1—Si1—C11^ii	−40.3 (5)	Si2^i—C1—Si2—C21	−160.6 (5)
Si2^ii—C1—Si1—C11^ii	−160.3 (5)	Si2^ii—C1—Si2—C21	−39.7 (8)
Si2—C1—Si1—C11^ii	79.7 (5)	Si1—C1—Si2—C21	79.9 (4)
Si2^i—C1—Si1—C11^i	−160.3 (5)	Si2^i—C1—Si2—C23	80.1 (7)
Si2^ii—C1—Si1—C11^i	79.7 (5)	Si2^ii—C1—Si2—C23	−159.0 (5)
Si2—C1—Si1—C11^i	−40.3 (5)	Si1—C1—Si2—C23	−39.5 (4)
Si2^i—C1—Si1—C11	79.7 (5)	Si2^i—C1—Si2—C22	−42.2 (7)
Si2^ii—C1—Si1—C11	−40.3 (5)	Si2^ii—C1—Si2—C22	78.8 (6)
Si2—C1—Si1—C11	−160.3 (5)	Si1—C1—Si2—C22	−161.7 (4)

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