Chlorartinite, a volcanic exhalation product also found in industrial magnesia screed

Abstract

The volcanic exhalation product chlorartinite, [Mg2(CO3)(H2O)(OH)]Cl·H2O, has recently been found to be a minor, and in some samples a major, component of magnesia floors for industrial use. In order to be able to perform quantitative phase analysis using the Rietveld method, its crystal structure was determined from high-resolution synchrotron powder diffraction data by the global optimization technique of simulated annealing and Rietveld refinement. The finalRpandRwpvalues are 5.23% and 6.56%, respectively. Chlorartinite crystallizes in the rhombohedral space groupR3c(No. 161), witha= 23.14422 (16) Å,c= 7.22333 (5) Å,V= 3350.84 (5) Å3,Z= 18. The building units of chlorartinite consist of MgO6octahedra forming 15-membered puckered rings which are interconnected by CO3triangular moieties. The rings are stacked to form a honeycomb-like three-dimensional framework structure with large isolated channels. Within the channels, free chlorine atoms and disordered water molecules are located.