Electron-diffraction investigation of the structure of the phenyltrifluorosilane molecule

Il'enko, T. M.; Veniaminov, N. N.; Алексеев, Н. В.

doi:10.1007/bf00747147

Cited by 2 publications

(1 citation statement)

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“…Therefore, it may be assumed that the negative charge is mainly responsible for the lengthening of the equatorial Si-F bonds in X5-Si fluorosilicates compared to the bonds in SiF4 or PhSiF3 (Si-F = 1.572 (6) A). 20 Substitution of fluorine by one or two less electronegative phenyl groups causes a consistent lengthening of the axial Si-F bond distances of 0.031 ([PhSiF4]")13 and 0.045 A. Contrary to this observation the equatorial bond lengths in [SiFs]~a re not significantly different from those in [PhSiF4]~.…”

Section: Discussionmentioning

confidence: 92%

Structural chemistry of pentacoordinated silicon. Molecular structures of the pentafluorosilicate anion and the diphenyltrifluorosilicate anion

Schomburg¹,

Krebs²

1984

Inorg. Chem.

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The X-ray structure determination of benzyltrimethylammonium pentafluorosilicate, [C6H5CH2N(CH3)3]+[SiF5]" (1), and tetramethylammonium diphenyltrifluorosilicate [(CH3)4N]+[(C6H5)2SiF3]~(2) shows that the anions are pentacoordinated at silicon and have a trigonal-bipyramidal geometry. The phenyl groups in 2 occupy equatorial positions of the TBP. In the diphenyl derivative 2 bond lengths to the axial and equatorial fluorine atoms are significantly longer than in 1. Both anions display crystallographic C2 symmetry with the axis passing through silicon and one of the equatorial ligands. 1 crystallizes in the orthorhombic space group Pbcm, with the following cell parameters at 170 K: a = 12.077 (1) Á, b = 7.855 (1) Á, c = 13.297 (1) Á, and Z = 4. 2 crystallizes in the trigonal space group P3221, with the cell parameters a = 8.8046 (5) Á, b = 18.4224 (17) A, and Z = 3. The final conventional residuals were 0.039 and 0.041 for 1 and 2, respectively.

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Section: Discussionmentioning

confidence: 92%