Mass Spectrum and Vapor Pressure of Pentaborane-d9

Abstract

The complete mass spectrum of pentaborane‐d₉ and a partial mass spectrum of pentaborane‐d₈ have been calculated from the spectra of a series of samples of different hydrogen content. The vapor pressure for pentaborane‐d₉ containing 3.9% of the B₅D₈H species can be expressed by the equation log₁₀P_mm=9.46916 — 0.0028783T — 1870.70/T over the temperature of — 25°C to +56°C. The melting point is — 47.0°C. By way of comparison the vapor pressure equation for pentaborane is log₁₀P_mm=9.49191 — 0.0028956T — 1881.29/T; the melting point is — 46.8°C.