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.
