A mass spectrometric investigation of the exchange of deuterium with tetraborane(10) in the gas phase

Abstract

Mass spectrometry has been used to establish direct exchange between dideuterium (D₂) and B₄H₁₀ in the gas phase. In a mixture of stoicheiometry B₄H₁₀ : 3D₂ at 42 °C, ca. 7% of the hydrogen atoms were replaced by deuterium in 130 min. The possibility that the exchange might be occurring by an indirect or autocatalytic mechanism was eliminated by a series of experiments in which the rate of exchange was shown to be independent of small admixtures of the decomposition products. The present work resolves a troublesome inconsistency in the literature and strengthens the view that the equilibrium B₄H₁₀⇌{B₄H₈}+ H₂ plays a key role in borane interconversion reactions.