Cyclopentasilane

Cyclopentasilane can be made from diphenyldichlorosilane (C6H5)2SiCl2 reacting with lithium. This forms decaphenylcyclopentasilane. This reacts with aluminium chloride in benzene catalysed with hydrogen chloride to yield decachlorocyclopentasilane. Decachlorocyclopentasilane then has its chlorine replaced by hydrogen using lithium aluminium hydride. ==Properties==

Cyclopentasilane is pyrophoric. It has a σ-delocalization property. Cyclopentasilane is a liquid at standard conditions, but can be frozen to crystals at 173K. The monoclinic crystals are not isomorphic to cyclopentane. The silicon to silicon bond lengths in the solid vary from 2.3353 and 2.3377 Å, which is shorter than in the substituted cyclopentasilanes or linear silanes. In gas form, those bond lengths, as measured by electron diffraction, increased to 2.342 Å. ==References==