s: Only tetrapotassium diphosphate is of major industrial importance, due to its high water solubility. It is produced in an analogous way to the sodium compound from dipotassium hydrogen phosphate.

Phosphates: The industrially most widely utilized calcium phosphates are:
(1) Ca(H₂PO₄)₂ - monocalcium phosphate (calcium dihydrogen phosphate) and
(2) CaHPO₄ - dicalcium phosphate (calcium hydrogen phosphate)
are produced by the reaction of calcium oxide, calcium hydroxide or other calcium salts with pure or post-purified phosphoric acid:

Both compounds are manufactured in anhydrous and hydrated forms.

Defluoridated apatite is obtained by heating apatite in a fluidized bed or rotary kiln at temperatures of ca. 1500°C in the presence of phosphorus or silica and steam.