Mass Spectrometric Identification of Si–O–H( <i>g</i> ) Species from the Reaction of Silica with Water Vapor at Atmospheric Pressure

Abstract

A high‐pressure sampling mass spectrometer was used to detect the volatile species formed from SiO 2 at temperatures between 1200° and 1400°C in a flowing water vapor/oxygen gas mixture at 1 bar total pressure. The primary vapor species identified was Si(OH) 4 . The fragment ion Si(OH) 3 + was observed in quantities 3 to 5 times larger than the parent ion Si(OH) 4 + . The Si(OH) 3 + intensity was found to have a small temperature dependence and to increase with the water vapor partial pressure as expected. In addition, SiO(OH) + , believed to be a fragment of SiO(OH) 2 , was observed. These mass spectral results were compared to the behavior of silicon halides.