As was mentioned in the "Corrosion" section of this manual, the solubility product of calcium and orthophosphate is very low. As a result, if orthophosphate is present in the water phase, it can react with calcium to form monohydrogen, dihydrogen and tricalcium phosphate. These phosphate sludges can bake onto heat exchange surfaces and, like other deposits, can both decrease heat transfer efficiency and yield underdeposit corrosion.
Iron(III) phosphate, also ferric orthophosphate, or ferric phosphate, FePO4, is a phosphate of iron. It is one of the few molluscicides approved for use in the practice of organic farming.
Orthophosphoric acid has three hydrogen atoms bonded to oxygen atoms in its structure. All three hydrogens are acidic to varying degrees and can be lost from the molecule as H+ ions (alternatively referred to as protons). When all three H+ ions are lost from orthophosphoric acid, an orthophosphate ion (PO43−) is formed.
Sodium hexametaphosphate (shmp) is a hexamer of composition (napo3)6.  sodium hexametaphosphate of commerce is typically a mixture of polymeric metaphosphates, of which the hexamer is one, and is usually the compound referred to by this name.
Trisodium phosphate (TSP) is a cleaning agent, food additive, stain remover and degreaser. It is a white, granular or crystalline solid, highly soluble in water producing an alkaline solution. The item of commerce is often partially hydrated and may range from anhydrous trisodium phosphate, Na3PO4, to the dodecahydrate, Na3PO4·12H2O. Most often found in white powder form, it can also be called trisodium orthophosphate or just plain sodium phosphate.