Deformation Mechanism of the LOSOD-Type Framework in Minerals of Bystrite Subgroup with a Change in Temperature and Chemical Composition

Abstract

A Low-temperature (100 K) analysis of the crystalline structures of Cl-bystrite and sulfhydrylbystrite has been carried out, and the data obtained have been compared with the room-temperature characteristics of these minerals. The framework deformations are considered as a result of change in the ditrigonality of six-membered tetrahedral rings: the decrease in the unit-cell volume at low temperature is determined mainly by the increase in the ditrigonality (compression) of six-membered framework rings. Oblique and vertical (corrugated) rings are distorted to a greater extent than horizontal rings. The deformation mechanisms is shown to be the same for the frameworks of bystrite-subgroup minerals and the sodalite framework.