2,2,5,5-Tetrakis(trimethylsilyl)-1,1,1,3,3,4,4,6,6,6-decamethylhexasilane, C22H66Si10, is a polysilane in which the longest chain is made up of six Si atoms and branching occurs at the second and fifth Si atoms. Each of the two central Si atoms is bonded to a tris(trimethylsilyl)silyl group in an anti arrangement. Bond lengths and angles are sufficiently close to normal to indicate that the molecule is relatively unstrained.