Investigations of raman spectra II—The raman spectra of perchloric acid and nitrosyl perchlorate

Abstract

The Raman spectrum of nitrosyl sulphate (nitrosylsulphuric acid) shows a strong frequency of 2311 cm -1 which we have attributed to the NO + group ( see Part I).* In order to verify this assignment, it seemed desirable that other nitrosyl compounds should be examined. Unfor­tunately the number of such compounds suitable for examination is very limited. The best-known nitrosyl compound is nitrosyl chloride, NOCl, but it is an orange-yellow gas, and therefore unsuitable for examination using the blue-violet mercury lines. It is also non-polar in character, and therefore would not show frequencies characteristic of the NO + group. The principal other nitrosyl compounds described in the literature are the perchlorate, borofluoride, and selenate. Of these the last two are not easy to prepare pure, and are unstable. An investigation of solid nitrosyl perchlorate has therefore been made, together with an examina­tion of the perchloric acid used in its preparation, and of solutions of nitrosyl perchlorate in perchloric acid.