Tripolyphosphoric acid

The P3093 ion (known as the trimetaphosphate ion) and (S03)3, a trimer of S03, also have this structure. The trimetaphosphate ion can be considered as the anion of the acid H3P309 (trimetaphos-phoric acid), a trimeric form of HP03 (metaphosphoric acid). Note that this acid is formally related to H5P3O10, tripolyphosphoric acid, by the reaction... 

Further condensation of phosphate groups leads to the polyphosphoric acids, which contain several phosphate units. The acids themselves are not particularly useful, but salts of some of these acids are used extensively. Triphosphoric acid, also known as tripolyphosphoric acid, H5P3O10, can be considered as a product of the reaction... 

Other polyphosphoric acids result from the sharing of oxygen atoms on the comer of tetrahedral PO4 units. Tripolyphosphoric acid, H5P3Oio, can be considered as being produced by the reaction... 

The product (H4P207) is called pyrophosphoric acid. Further heating produces polymers, such as tripolyphosphoric acid (H5P3O10), which has the structure... 

The sodium salt of tripolyphosphoric acid is widely used in detergents because the P30io5- anion can form complexes with metal ions such as Mg2+ and Ca2+, which would otherwise interfere with detergent action. 

Tripolyphosphoric acid—A condensed phosphate of the formnla H5P30,o. 

Polyphosphoric Acid. Phospholeum tetraphos-phoric add. May be prepd by heating HjPO, with sufficient phosphoric anhydride to give the resulting product an 82-85" PjO, content Ball, Ind, Eng. Chem. 44), 1464 (1949) Van Wazer, Holst, J- Am. Chem. Soc. 72, 639 (1950) Ken-nard, Org. Chem. Bull 29, no. 1 (1957). Consists of about 55% tripolyphosphoric acid, the remainder being HjP04 and other polyphosphoric acids. Typical analysts 83.0% PjOs ortho equivalent 115.0%. 

The dehydration reaction (elimination of H2O) between phosphoric acid (H3PO4) and diphosphoric acid (H4P2O7) results in the molecule H5P3O10 or tripolyphosphoric acid. A further dehydration reaction with phosphoric acid results in the formation of H6P4O13 or tetrapolyphosphoric acid. 

Diphosphates. Improved values for the dissociation constants of diphosphoric and tripolyphosphoric acids have been calculated. The effect of the pressure of water vapour on the reaction ... 

E. Prodan and I. L. Shashkova [Kinet. Catal., 24, 891-894 (1984)] studied the kinetics of the decomposition of tripolyphosphoric acid in aqueous solution. The decomposition involves the following reactions ... 

Non-metals and metalloids with medium electronegativity values (P, As, S and Se) form covalent compoimds in biological systems, such as esters of phosphoric, pyrophosphoric and tripolyphosphoric acids, sulfur amino acids and then-selenium analogues, arsenic analogues of amino compounds and sulfur heterocycles. 

How many acidic protons are there in tripolyphosphoric acid and tripolyphospho-rous acid Draw structures of these acids that verify your answer. 

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