Crystal and molecular structure of tetra(methylsilicon) hexasulphide (1,3,5,7-tetramethyl-2,4,6,8,9,10-hexathia-1,3,5,7-tetrasila-adamantane)

Abstract

The crystal structure of the title compound has been determined by single-crystal X-ray diffraction methods. Crystals are monoclinic, space group C2/c, with a= 9.382(10), b= 16.513(20), c= 10.584(11)Å, β= 107° 10(10)′, and Z= 4. The structure was solved by direct methods and refined by block-diagonal least-squares techniques to R 4.4% for 1 284 independent reflections measured by diffractometer. The molecule exhibits the crystallographically required C₂ symmetry and approximates closely to T_d(3m) symmetry like the corresponding Ge and Sn compounds. Mean molecular parameters in the adamantane-type structure are: Si–S 2.129, Si–C 1.836 Å; Si–S–Si 104.6, S–Si–S 111.8, and S–Si–C 107.0°. The Si valence angles show a smaller distortion from the tetrahedral value than do those at S. The molecular conformation and crystal packing are compared with that in other hexathia-adamantanes.