A safe and efficient synthetic method for alkali metal octahydrotriborates, unravelling a general mechanism for constructing the delta B3 unit of polyhedral boranes

A safe and efficient synthetic method for MB 3 H 8 (M = Na, K, Rb and Cs) has been developed with excellent yields by directly reacting the corresponding MBH 4 with the dimethyl sulfide borane complex (DMS·BH 3 ). A general mechanism for constructing B 3 H 8 − , a basic unit for building polyhedral boranes, has been unravelled. An efficient synthetic method for KB 3 H 8 has been developed and general mechanisms of formation of the B 3 H 8 − anion have been elucidated.