Phase Diagrams to High Pressures of the Univalent Azides Belonging to the Space GroupD4h18hyphen;I4thinsp;sol;thinsp;mcm

摘要

The highhyphen;pressure phase diagrams of CsN3, TlN3, RbN3, and KN3were studied by means of differential thermal analysis and volume displacement. These substances decompose explosively near sim;thinsp;460deg;C even at high pressures. CsN3, TlN3, and RbN3each have a new highhyphen;pressure transformation with a volume change of sim;thinsp;3.5percnt; near 6 kbar at 25deg;C. The transition pressures increase with temperature. In the case of CsN3this transition line meets the tetragonal/bcc transition line at a triple point at 173deg;C, 8 kbar. The resulting CsN3III/bcc phase boundary was followed to 37 kbar, where it is terminated by explosive decomposition. The TlN3tetragonal/bcc boundary was followed to 20 kbar, where it is also terminated. The melting curves of KN3and TlN3were followed only to sim;thinsp;5 kbar, where they are terminated.