The action of ultra-violet radiation on barium and strontium azides

Abstract

The alkaline earth azides decompose at appreciable rates at temperatures above 100° C, and the reactions which occur are of the accelerating type increasing in speed as the 6th-8th power of the time, there being a marked induction period during which the reaction occurs at a negligible rate (Harvey 1933; Marke 1937; Maggs 1939). The decomposition is accelerated and the length of the induction period shortened when the solid is acted upon by β -rays at room temperature before the heat treatment (Garner and Moon 1933; Maggs 1939). It was, therefore, possible that ultra-violet light would cause an acceleration of these reactions in a similar manner. Muller and Brous (1933) have shown that sodium azide is decomposed by ultra-violet light at a rate which is proportional to the intensity and that the threshold wave-length for the decomposition is around 405 m µ . In the present investigation it is shown that barium and strontium azides are decomposed by ultra-violet light at room temperature and that the thermal decomposition of these substances is accelerated by pre-treatment with this radiation.