Part.3 : PHOSPHATES
PHOSPHATES
ionic bond → anisodesmic
key structural element is presence of tetrahedral PO₄³- anionic groups, & phosphorus ions have +5 charge, so phosphate groups anisodesmic
Only few phosphate minerals likely to be encountered routinely, Apatite, monazite, xenotime, & Turquoise
The principal compositional variation is in the relative amounts of OH, F, & Cl
Fluorapatite Ca₅(PO₄)₃F
Hydroxylapatire Ca₅(PO₄)₃OH
Chlorapatite Ca₅(PO₄)₃Cl
Environmental and applied geology 