Phosphate minerals contain the tetrahedrally coordinated phosphate (PO 4 3−) anion, sometimes with arsenate (AsO 4 3−) and vanadate (VO 4 3−) substitutions, along with chloride (Cl −), fluoride (F −), and hydroxide (OH −) anions, that also fit into the crystal structure.. The phosphate class of minerals is a large and diverse group, however, only a few species are relatively common.