Triphosphoric acid (also tripolyphosphoric acid), with formula H
5P
3O
10, is a
condensed form of
phosphoric acid
Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, ...
. In the family of
phosphoric acids, it is the next
polyphosphoric acid
In chemistry, a phosphoric acid, in the general sense, is a phosphorus acid, phosphorus oxoacid in which each phosphorus (P) atom is in the oxidation state +5, and is chemical bond, bonded to four oxygen (O) atoms, one of them through a double b ...
after
pyrophosphoric acid
Pyrophosphoric acid, also known as diphosphoric acid, is the inorganic compound with the formula H4P2O7 or, more descriptively, HO)2P(O)sub>2O. Colorless and odorless, it is soluble in water, diethyl ether, and ethyl alcohol. The anhydrous aci ...
, H
4P
2O
7, also called diphosphoric acid.
Compounds such as ATP (
adenosine triphosphate
Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known ...
) are
ester
In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...
s of triphosphoric acid.
Triphosphoric acid has not been obtained in crystalline form. The equilibrium mixture with an overall composition corresponding to H
5P
3O
10 contains about 20% of triphosphoric acid. A solution of the pure species can be obtained by ion exchange of the sodium salt,
sodium triphosphate, at 0 °C.
Triphosporic acid is a
pentaprotic acid, meaning that it can release five protons in basic enough conditions. Sources differ on the corresponding p''K''
a values:
* 1.0; 2.2; 2.3; 5.7; 8.5
* 1.0; 2.2; 2.3; 3.7; 8.5
* small; small; 2.30; 6.50; 9.24
References
Phosphorus oxoacids
Phosphorus(V) compounds
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