Chemistry of boranes. XXVII. New polyhedral borane anions, B9H92- and B11H112-

Article abstract of DOI:10.1021/ic50045a027

Salts of two novel polyhedral borane anions, B₉H₉^2- and B₁₁H₁₁^2-, have been prepared and characterized. The alkali metal salts of B₉H₉^2- possess a high thermal stability comparable to that of the salts of B₁₀H₁₀^2- and B₁₂H₁₂^2-. At 600°, Cs₂B₁₁H₁₁ is converted to a mixture of Cs₂B₁₀H₁₀ and Cs₂B₁₂H₁₂. The B₉ and B₁₁ anions are hydrolytically unstable in acidic media; the B₉ anion is more rapidly degraded than the B₁₁ anion. In solution, the B₉H₉^2- ion appears to be best described as a symmetrically tricapped trigonal prism (D_3h) of boron atoms each of which has a terminally attached hydrogen atom.