MASS SPECTROMETRIC STUDY OF SUBLIMING SELENIUM

Abstract

In the mass spectrum of the vapor from grey selenium subliming in the temperature range 102 to 187 °C all possible Se_n⁺ ions between n = 1 and n = 8 were detected in measurable quantities. The ions Se₅⁺, Se₆⁺, Se₇⁺, and Se₈⁺ arise mainly from ionization of the corresponding parent molecules, which are believed to be cyclic. At 175 °C the composition of the vapor is Se₅ ≤ 29.0%, Se₆ ≥ 57.5%, Se₇ ≥ 11.4%, and Se₈ ≥ 2.0%. Thermodynamic data are reported for the sublimation of these molecules. Small amounts of Se₉⁺ and Se₁₀⁺ were also detected.