(Tri­methyl­silyl)­acetyl­ene

The crystal structure of (tri­methyl­silyl)­acetyl­ene, C₅H₁₀Si, (I), has been determined at 150 K. In space group P2₁, there are three independent mol­ecules in the asymmetric unit.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.096
• wR factor = 0.273
• Data-to-parameter ratio = 20.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level B:



DIFMX_01  Alert B The maximum difference density is > 0.1*ZMAX*1.00
          _refine_diff_density_max given =      1.532
          Test value =      1.400


 Alert Level C:



DIFMX_02  Alert C The minimum difference density is > 0.1*ZMAX*0.75
          The relevant atom site should be identified.

RFACR_01  Alert C The value of the weighted R factor is > 0.25
          Weighted R factor given   0.273

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           27.46
         From the CIF: _reflns_number_total               3566
         Count of symmetry unique reflns         2706
         Completeness (_total/calc)            131.78%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       860
         Fraction of Friedel pairs measured     0.318
         Are heavy atom types Z>Si present          yes
          WARNING: Large fraction of Friedel related reflns may
                   be needed to determine absolute structure


 0 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 2 Alert Level C = Please check

---

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Sheldrick, 1993); software used to prepare material for publication: SHELXL97.

(I)

Crystal data

C5H10Si	Dx = 0.912 Mg m^−3
Mr = 98.22	Melting point: 265 K
Monoclinic, P21	Mo Kα radiation, λ = 0.7107 Å
a = 10.868 (2) Å	Cell parameters from 16948 reflections
b = 5.742 (1) Å	θ = 1.0–27.5°
c = 17.190 (2) Å	µ = 0.21 mm^−1
β = 91.31 (1)°	T = 150 K
V = 1072.4 (3) Å^3	Cylinder, colourless
Z = 6	0.15 mm (radius)
F(000) = 324

Data collection

Nonius KappaCCD diffractometer	2955 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.069
Graphite monochromator	θmax = 27.5°, θmin = 3.6°
Thin–slice ω and φ scans	h = −13→9
5343 measured reflections	k = −5→7
3566 independent reflections	l = −21→22

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)] = 0.096	H-atom parameters constrained
wR(F^2) = 0.273	w = 1/[σ^2(Fo^2) + (0.1617P)^2 + 1.4254P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
3566 reflections	Δρmax = 1.53 e Å^−3
177 parameters	Δρmin = −0.52 e Å^−3
25 restraints	Absolute structure: Flack (1983), 860 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.1 (4)

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
Si1A	0.77397 (12)	0.2544 (3)	0.59596 (8)	0.0386 (4)
C1A	0.6713 (6)	0.0708 (11)	0.6558 (4)	0.0554 (16)
H1AA	0.7212	−0.0207	0.6929	0.106 (7)*
H1AB	0.6239	−0.0346	0.6218	0.106 (7)*
H1AC	0.6149	0.1709	0.6843	0.106 (7)*
C2A	0.8694 (6)	0.0753 (12)	0.5309 (4)	0.0584 (17)
H2AA	0.9033	−0.0577	0.5599	0.106 (7)*
H2AB	0.9369	0.1702	0.5112	0.106 (7)*
H2AC	0.8184	0.0188	0.4870	0.106 (7)*
C3A	0.8712 (7)	0.4445 (13)	0.6599 (4)	0.072 (2)
H3AA	0.9167	0.3483	0.6978	0.106 (7)*
H3AB	0.8186	0.5543	0.6875	0.106 (7)*
H3AC	0.9294	0.5311	0.6282	0.106 (7)*
C4A	0.6767 (5)	0.4434 (10)	0.5356 (3)	0.0428 (13)
C5A	0.6078 (6)	0.5668 (11)	0.4989 (4)	0.0495 (15)
H5A	0.5532	0.6646	0.4698	0.085 (15)*
Si1B	0.27337 (12)	−0.2583 (3)	0.73718 (8)	0.0388 (4)
C1B	0.1643 (6)	−0.0761 (12)	0.6804 (4)	0.0560 (16)
H1BA	0.2091	0.0121	0.6413	0.106 (7)*
H1BB	0.1231	0.0323	0.7154	0.106 (7)*
H1BC	0.1028	−0.1758	0.6545	0.106 (7)*
C2B	0.3760 (6)	−0.0761 (13)	0.7980 (4)	0.0606 (18)
H2BA	0.4414	−0.0122	0.7660	0.106 (7)*
H2BB	0.4125	−0.1707	0.8400	0.106 (7)*
H2BC	0.3287	0.0519	0.8203	0.106 (7)*
C3B	0.3628 (7)	−0.4493 (13)	0.6718 (4)	0.072 (2)
H3BA	0.4060	−0.3532	0.6341	0.106 (7)*
H3BB	0.3066	−0.5559	0.6442	0.106 (7)*
H3BC	0.4228	−0.5393	0.7028	0.106 (7)*
C4B	0.1828 (5)	−0.4429 (10)	0.8016 (3)	0.0420 (13)
C5B	0.1204 (6)	−0.5687 (12)	0.8398 (4)	0.0606 (17)
H5B	0.0709	−0.6686	0.8700	0.085 (15)*
Si1C	0.73769 (14)	0.2579 (3)	0.92845 (8)	0.0456 (4)
C1C	0.6347 (7)	0.0704 (13)	0.9848 (4)	0.0638 (19)
H1CA	0.5789	0.1678	1.0148	0.106 (7)*
H1CB	0.6839	−0.0275	1.0203	0.106 (7)*
H1CC	0.5865	−0.0288	0.9491	0.106 (7)*
C2C	0.8319 (7)	0.4425 (13)	0.9946 (4)	0.0652 (19)
H2CA	0.7780	0.5276	1.0296	0.106 (7)*
H2CB	0.8792	0.5536	0.9641	0.106 (7)*
H2CC	0.8885	0.3442	1.0254	0.106 (7)*
C3C	0.6474 (7)	0.4375 (14)	0.8580 (4)	0.067 (2)
H3CA	0.5876	0.5317	0.8860	0.106 (7)*
H3CB	0.6038	0.3355	0.8209	0.106 (7)*
H3CC	0.7030	0.5402	0.8299	0.106 (7)*
C4C	0.8390 (6)	0.0638 (11)	0.8740 (4)	0.0522 (16)
C5C	0.9011 (7)	−0.0681 (13)	0.8393 (4)	0.0643 (19)
H5C	0.9508	−0.1738	0.8114	0.085 (15)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Si1A	0.0366 (8)	0.0334 (8)	0.0456 (7)	−0.0001 (12)	−0.0055 (5)	0.0035 (9)
C1A	0.064 (4)	0.047 (4)	0.056 (3)	−0.004 (3)	0.009 (3)	0.001 (3)
C2A	0.046 (4)	0.051 (4)	0.078 (4)	0.008 (3)	0.010 (3)	0.012 (4)
C3A	0.076 (5)	0.054 (4)	0.085 (5)	−0.012 (4)	−0.035 (4)	0.012 (4)
C4A	0.033 (3)	0.043 (3)	0.052 (3)	−0.006 (3)	−0.003 (2)	−0.008 (3)
C5A	0.044 (3)	0.039 (3)	0.064 (3)	0.006 (3)	−0.016 (3)	0.003 (3)
Si1B	0.0314 (7)	0.0350 (9)	0.0500 (7)	−0.0001 (11)	0.0011 (5)	0.0012 (9)
C1B	0.051 (4)	0.059 (4)	0.058 (4)	−0.002 (3)	−0.012 (3)	0.003 (3)
C2B	0.052 (4)	0.060 (4)	0.070 (4)	−0.007 (4)	−0.006 (3)	0.004 (4)
C3B	0.088 (6)	0.048 (4)	0.081 (5)	0.015 (4)	0.042 (4)	0.007 (4)
C4B	0.034 (3)	0.039 (3)	0.053 (3)	0.001 (3)	0.001 (2)	−0.003 (3)
C5B	0.054 (4)	0.050 (4)	0.078 (4)	0.000 (3)	0.011 (3)	0.003 (3)
Si1C	0.0543 (10)	0.0375 (9)	0.0449 (7)	0.0076 (10)	0.0018 (6)	−0.0007 (9)
C1C	0.061 (5)	0.060 (4)	0.071 (4)	−0.004 (4)	0.019 (4)	−0.002 (4)
C2C	0.065 (5)	0.057 (4)	0.073 (4)	−0.003 (4)	−0.014 (4)	−0.006 (4)
C3C	0.069 (5)	0.079 (5)	0.052 (3)	0.026 (4)	−0.008 (3)	−0.010 (4)
C4C	0.052 (4)	0.052 (4)	0.052 (3)	0.009 (3)	0.009 (3)	0.007 (3)
C5C	0.058 (4)	0.058 (4)	0.077 (4)	0.011 (4)	0.008 (4)	0.003 (4)

Geometric parameters (Å, º)

Si1A—C4A	1.823 (5)	C2B—H2BB	0.980
Si1A—C2A	1.854 (6)	C2B—H2BC	0.980
Si1A—C3A	1.861 (6)	C3B—H3BA	0.980
Si1A—C1A	1.862 (6)	C3B—H3BB	0.980
C1A—H1AA	0.980	C3B—H3BC	0.980
C1A—H1AB	0.980	C4B—C5B	1.197 (8)
C1A—H1AC	0.980	C5B—H5B	0.950
C2A—H2AA	0.980	Si1C—C4C	1.837 (6)
C2A—H2AB	0.980	Si1C—C1C	1.844 (6)
C2A—H2AC	0.980	Si1C—C2C	1.848 (6)
C3A—H3AA	0.980	Si1C—C3C	1.854 (6)
C3A—H3AB	0.980	C1C—H1CA	0.980
C3A—H3AC	0.980	C1C—H1CB	0.980
C4A—C5A	1.200 (7)	C1C—H1CC	0.980
C5A—H5A	0.950	C2C—H2CA	0.980
Si1B—C4B	1.836 (6)	C2C—H2CB	0.980
Si1B—C2B	1.838 (6)	C2C—H2CC	0.980
Si1B—C1B	1.843 (6)	C3C—H3CA	0.980
Si1B—C3B	1.860 (6)	C3C—H3CB	0.980
C1B—H1BA	0.980	C3C—H3CC	0.980
C1B—H1BB	0.980	C4C—C5C	1.185 (8)
C1B—H1BC	0.980	C5C—H5C	0.950
C2B—H2BA	0.980
C4A—Si1A—C2A	108.1 (3)	Si1B—C2B—H2BB	109.5
C4A—Si1A—C3A	107.5 (3)	H2BA—C2B—H2BB	109.5
C2A—Si1A—C3A	111.4 (3)	Si1B—C2B—H2BC	109.5
C4A—Si1A—C1A	107.8 (3)	H2BA—C2B—H2BC	109.5
C2A—Si1A—C1A	111.7 (3)	H2BB—C2B—H2BC	109.5
C3A—Si1A—C1A	110.2 (3)	Si1B—C3B—H3BA	109.5
Si1A—C1A—H1AA	109.5	Si1B—C3B—H3BB	109.5
Si1A—C1A—H1AB	109.5	H3BA—C3B—H3BB	109.5
H1AA—C1A—H1AB	109.5	Si1B—C3B—H3BC	109.5
Si1A—C1A—H1AC	109.5	H3BA—C3B—H3BC	109.5
H1AA—C1A—H1AC	109.5	H3BB—C3B—H3BC	109.5
H1AB—C1A—H1AC	109.5	C5B—C4B—Si1B	176.1 (6)
Si1A—C2A—H2AA	109.5	C4B—C5B—H5B	180.0
Si1A—C2A—H2AB	109.5	C4C—Si1C—C1C	106.9 (4)
H2AA—C2A—H2AB	109.5	C4C—Si1C—C2C	109.4 (3)
Si1A—C2A—H2AC	109.5	C1C—Si1C—C2C	110.3 (3)
H2AA—C2A—H2AC	109.5	C4C—Si1C—C3C	108.6 (3)
H2AB—C2A—H2AC	109.5	C1C—Si1C—C3C	110.4 (4)
Si1A—C3A—H3AA	109.5	C2C—Si1C—C3C	111.1 (4)
Si1A—C3A—H3AB	109.5	Si1C—C1C—H1CA	109.5
H3AA—C3A—H3AB	109.5	Si1C—C1C—H1CB	109.5
Si1A—C3A—H3AC	109.5	H1CA—C1C—H1CB	109.5
H3AA—C3A—H3AC	109.5	Si1C—C1C—H1CC	109.5
H3AB—C3A—H3AC	109.5	H1CA—C1C—H1CC	109.5
C5A—C4A—Si1A	176.4 (6)	H1CB—C1C—H1CC	109.5
C4A—C5A—H5A	180.0	Si1C—C2C—H2CA	109.5
C4B—Si1B—C2B	108.2 (3)	Si1C—C2C—H2CB	109.5
C4B—Si1B—C1B	107.4 (3)	H2CA—C2C—H2CB	109.5
C2B—Si1B—C1B	110.6 (3)	Si1C—C2C—H2CC	109.5
C4B—Si1B—C3B	108.6 (3)	H2CA—C2C—H2CC	109.5
C2B—Si1B—C3B	111.1 (4)	H2CB—C2C—H2CC	109.5
C1B—Si1B—C3B	110.7 (3)	Si1C—C3C—H3CA	109.5
Si1B—C1B—H1BA	109.5	Si1C—C3C—H3CB	109.5
Si1B—C1B—H1BB	109.5	H3CA—C3C—H3CB	109.5
H1BA—C1B—H1BB	109.5	Si1C—C3C—H3CC	109.5
Si1B—C1B—H1BC	109.5	H3CA—C3C—H3CC	109.5
H1BA—C1B—H1BC	109.5	H3CB—C3C—H3CC	109.5
H1BB—C1B—H1BC	109.5	C5C—C4C—Si1C	177.5 (7)
Si1B—C2B—H2BA	109.5	C4C—C5C—H5C	180.0