Table 1: pH-dependency of phosphoric acids and its salts [55]. All these ions can interact with calcium ions, which lead to a huge variety of calcium phosphate phases.

pH Mol-%
-0.5 100% H3PO4
2 50% H3PO4, 50% H2PO4-
4.5 100% H2PO4-
6 90% H2PO4-, 10% HPO42-
8 10% H2PO4-, 90% HPO42-
9.5 100% HPO42-
12 50% HPO42-, 50% PO43-
14.5 100% PO43-