Phosphate

A phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid, a.k.a. phosphoric acid H3PO4. The phosphate or orthophosphate ion PO43− is derived from phosphoric acid by the removal of three protons H+. Removal of one proton gives the dihydrogen phosphate ion H2PO4− while removal of two protons gives the hydrogen phosphate ion HPO42−. These names are also used in chemistry for salts of those anions, such as ammonium dihydrogen phosphate and trisodium phosphate. In organic chemistry, phosphate or orthophosphate is an organophosphate, an ester of orthophosphoric acid of the form PO4RR′R″ where one or more hydrogen atoms are replaced by organic groups. An example is trimethyl phosphate, (CH3)3PO4. The term also refers to the trivalent functional group OP(O−)3 in such esters. Phosphates may contain sulfur in place of one or more oxygen atoms (thiophosphates and organothiophosphates). Orthophosphates are especially important among the various phosphates because of their key roles in biochemistry, biogeochemistry, and ecology, and their economic importance for agriculture and industry. The addition and removal of phosphate groups (phosphorylation and dephosphorylation) are key steps in cell metabolism. Phosphates are a major component of agricultural fertilizers and play an important role in plant growth. Since phosphates stimulate plant growth, too much phosphate in the environment can cause pollution in the environment and lead to excessive plant growth. Phosphates are mined around the world for use in agriculture and industry. Mining is a source of heavy metal pollution. Orthophosphates can condense to form pyrophosphates.