What is "triphosphoric acid"

n. (context chemistry English) a condensation product of phosphoric acid, H₅P₃O₁₀, known from its salts and esters

n. an acid that is a partial anhydride of three molecules of phosphoric acid; known chiefly in the form of its salts and esters

Triphosphoric acid (also tripolyphosphoric acid), with formula HPO, is a condensed form of phosphoric acid. In the family of phosphoric acids, it is the next polyphosphoric acid after pyrophosphoric acid, HPO, also called diphosphoric acid.

Compounds such as ATP ( adenosine triphosphate) are esters of triphosphoric acid.

Triphosphoric acid has not been obtained in crystalline form. The equilibrium mixture with an overall composition corresponding to HPO contains about 18% of triphosphoric acid. A solution of the pure species can be obtained by ion exchange of the sodium salt, sodium triphosphate, at 0 °C.

Various pK values are reported, 1.0 ; 2.2 ; 2.3 ; 5.7 ; 8.5, 1.0 ; 2.2 ; 2.3 ; 3.7 ; 8.5