Mass Spectrometric Study of the B2D6–B5H9 Exchange Reaction

Abstract

The distribution of partially deuterated pentaborane species resulting from the reaction between B₂D₆–B₅H₉ and its converse B₂H₆–B₅D₉ has been examined mass spectroscopically. It was found that the deuterium is entering the pentaborane by two main processes; namely exchange and synthesis by pyrolysis of diborane. The number of readily exchangeable positions in the pentaborane under our experimental conditions is five. If the remaining four hydrogens are exchanging they are doing so at a very much slower rate. Examination of the mass spectrum indicates that the deuteriums are entering the molecule singly during exchange. Tracer studies with B¹⁰ indicate that borons are not involved in the exchange.