CRYSTAL-STRUCTURE OF AUSTINITE, CAZN(ASO4)OH

Austinite belongs to the adelite mineral group of calcium and lead ars enates, and has the conichalcite/descloizite type of crystal structure . The crystal structure of nearly pure austinite, CaZn(AsO4)OH, was re determined (R = 0.014) and the absolute configuration identified. The space group P2(1)2(1)2(1) and cell parameters a 7.5092(8), b 9.0438(9) , c 5.9343(8) Angstrom 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 antip risms share edges to make chains parallel to a that occupy the channel s in the zinc-arsenic framework.