Crystal Structure of Austinite, CaZn(AsO4)OH

Lori A. Clark, Joseph J. Pluth, Ian Steele, Joseph V. Smith and Stephen R. Sutton
Department of Geophysical Sciences, University of Chicago, Chicago, Illinois 60637, USA
Department of Geophysical Sciences and Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637, USA

Abstract: Austinite belongs to the adelite mineral group of calcium and lead arsenates, and has the conichalcite/descloizite type of crystal structure. The crystal structure of nearly pure austinite, CaZn(AsO4)OH, was redetermined (R = 0.014) and the absolute configuration identified. The space group P212121 and cell parameters a 7.5092(8), b 9.0438(9), c 5.9343(8) Å match previous data. Zinc octahedra share edges to form chains parallel to c. Arsenic tetrahedra share vertices with the Zn octahedra to generate a compact framework. Calcium square antiprisms share edges to make chains parallel to a that occupy the channels in the zinc-arsenic framework.

Keywords: austinite • crystal structure • adelite group

Mineralogical Magazine; October 1997 v. 61; no. 408; p. 677-683; DOI: 10.1180/minmag.1997.061.408.06
© 1997, The Mineralogical Society
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