Metaphosphoric acid (inci)

Metaphosphoric acid, the metaphosphoric acid is a substance with the molecular formula: HPO3. Metaphosphoric acid does not exist as an acid or as a salt in monomeric form. Rather, metaphosphoric acid condenses to ring-shaped molecular structures. These have the general formula (HPO3)n.

The metaphosphoric acid with n = 3 HPO3 is called trimetaphosphoric acid, the metaphosphoric acid with n = 4 HPO3 is called tetrametaphosphoric acid. The salts of metaphosphoric acid are called metaphosphates.

Metaphosphoric acid is used in cosmetic formulations. The acid acts as a buffer (stabilizes the pH value). It also forms complexes with metal ions which may influence the stability and/or appearance of cosmetic products.