H3PO4H2PO4

H3PO4H2PO4 is not a recognized chemical compound or formula. It appears to be a misunderstanding or a typo. The standard chemical formula for phosphoric acid is H3PO4. Phosphoric acid is a triprotic acid, meaning it can donate three protons (H+ ions). Its dissociation in water occurs in three steps, producing various phosphate ions. The first dissociation produces the dihydrogen phosphate ion, H2PO4-. The second dissociation produces the hydrogen phosphate ion, HPO4(2-). The third dissociation produces the phosphate ion, PO4(3-). Therefore, H3PO4 and H2PO4- are distinct chemical species, with H2PO4- being a product of the dissociation of H3PO4. There is no stable compound formed by simply combining H3PO4 and H2PO4- in a 1:1 ratio as suggested by the notation H3PO4H2PO4. It is possible that the notation refers to a mixture of phosphoric acid and its conjugate base, the dihydrogen phosphate ion, in a solution, but this is not represented as a single chemical formula.