Barium Chloroapatite

Description

Barium chloroapatite is hexagonal with space group of P63/m and a = 10.284 ?, c = 7.651 ?, V = 602.003 ? 3, Z = 2 and point group of 6/m. The following table shows the position of the various ions in the hexagonal structure. Thus, the Cl^- ion is located at (000) and (1/2, 1/2, 1/2) while the others lie at points in between. Ba1 lies at (0.3333, 0.6667, 0.6667) while Ba2 is at (0.2445, 0.2606, 0.2500).
This salt occurs as a natural mineral having the same composition, except the ore is contaminated by other metallic minerals as well. “Alforsite”, ideally Ba5(PO4)3CI is a new member of the apatite group occurring in contact with metamorphosed vaporitic rocks from Fresno and Mariposa Counties, California, associated with fluorapatite and many other rare barium minerals previously described by Alfors et al (1965). It is optically uniaxial, negative, with u, ε=1.70.