Phosphite (HPO32−) is the anion of phosphorous acid (H3PO3), an oxide of phosphorus in which the phosphorus has a +3 valence state. In contrast to orthophosphate dissolved in solution, in phosphite one hydrogen atom is directly bound to the central P atom, instead of being bound through an O atom. Phosphite is more soluble in ocean water than phosphate. Oxidation of phosphite yields phosphate and, under certain conditions, also pyrophosphate and larger polyphosphates. Phosphite on the Earth may have originated from corrosion of iron-rich meteorites or from reduction of phosphate by lightning strikes or other high-energy events, and may have comprised some portion of the total phosphorus in the early Archean oceans.