Mass-spectrometric study of the thermal pyrolysis of tetrasulphur tetranitride over quartz wool and silver wool

Abstract

Mass-spectrometric techniques have been used to identify the pyrolysis products of S₄N₄ vapours passed over quartz wool and silver wool at 80–400 °C. Tetrasulphur tetranitride was volatilized from solid samples at 60–80 °C in a heated tube and passed into a second reaction tube packed with quartz or silver wool heated to 80–400 °C. The products passing from the reaction tube are examined using modulated molecular-beam techniques in conjunction with measurements of the mass-spectrometric appearance potentials, low-energy electron-impact mass spectrometry, and phase-angle spectrometry. The major product at ca. 200 °C is S₂N₂, accompanied by smaller amounts of S₃N₃ and S₄N₂. At higher temperatures (>300 °C) S₂, SN, and N₂ become the major pyrolysis products. The results are examined in terms of their implications for the synthesis of (SN)_x from S₂N₂ and S₄N₄.