Journal of Applied Crystallography

Volume 39, Part 5 (October 2006)

research papers

J. Appl. Cryst. (2006). 39, 739-744 [ doi:10.1107/S0021889806032109 ]

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

K. Sugimoto, R. E. Dinnebier and T. Schlecht

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 final R_p and R_wp values are 5.23% and 6.56%, respectively. Chlorartinite crystallizes in the rhombohedral space group R3c (No. 161), with a = 23.14422 (16) Å, c = 7.22333 (5) Å, V = 3350.84 (5) Å³, Z = 18. The building units of chlorartinite consist of MgO₆ octahedra forming 15-membered puckered rings which are interconnected by CO₃ triangular 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.

Keywords: chlorartinite; magnesia screed; quantitative phase analysis; inclusion compounds; channel structure.