Diphosphoric

Two examples of condensed phosphoricfV) acids are heptaoxo-diphosphoric(V) (pyrophosphoric) and polytrioxophosphoric (meta-phosphoric) acids. 

H3AS04 arsenic acid H4P2O2 diphosphoric acid (or pyro-... 

See also pyrophosphorous acid.) [PHOSPHORUS COMPOUNDS] (Vol 18) Diphosphoric(III,V) acid [14902-77-3]... 

Pyrophosphoric (diphosphoric) acid, H4P2O2, is the only condensed phosphoric acid definitely obtainable ia crystalline form. It has a theoretical P2O5 content of 79.8%. However, Hquid polyphosphoric acid of such content shows by analysis only 42.5% the remainder is phosphoric acid and... 

Orthophosphoric acid is a remarkable substance it can only be obtained pure in the crystalline state (mp 42.35°C) and when fused it slowly undergoes partial self-dehydration to diphosphoric acid ... 

As diphosphoric acid is tetrabasic, four series of salts are possible though not all are always known, even for simple cations. The most studied are those of Na, K, NH4 and Ca, e.g. ... 

Chemical Name 2-Methyl-l, 4-naphthalenediol diphosphoric acid ester tetrasodium salt Common Name —... 

There also exists interference from diphosphoric acid, other more highly condensed phosphoric acids, and their organic derivatives. The free phosphoric acid can be determined as a heteropolyacid complex of phosphoric acid and ammonium molybdate. Afterward the complex is reduced by stannum II chloride to molybdenum blue. The amount of this dye can be measured photometricly at 625 nm. Organic derivatives of phosphoric acid and condensed phosphoric acids do not interfere with this method. 

If a sugar is esterified with two or more phosphate groups, the compound is termed bisphosphate, trisphosphate etc. (e.g. fructofuranose 1,6-bisphosphate). The term diphosphate denotes an ester with diphosphoric acid, e.g. adenosine S -diphosphate. 

Ci0H15N5O10P2 -3 HaO Adenosine 5 -diphosphoric acid, trihydrate ADENDP20 43 334... 

Nucleoside triphosphates are prepared analogously to the diphosphates by the methods a, b, c, and d, representing conversion of a nucleoside phosphoric azolide with inorganic pyrophosphate (Method a), of a nucleoside diphosphoric azolide with inorganic phosphate (Method b), of a phosphoric bisazolide with a nucleoside diphosphate (Method c), and of a diphosphoric bisazolide (bisazolide of pyrophosphoric acid) with a nucleoside phosphate (Method d). 

HP03/ which is known as metaphosphoric acid, and it is a strong acid. We can view the formation of ff4P207 (known as diphosphoric acid or pyrophosphoric acid) as arising from the addition of P205 to ff3P04 or the removal of a molecule of water from two molecules of H3P04. The first process can be shown as... 

May spontaneously ignite in air if traces of diphosphorous hydride (P2H2) are present. 

Phosphatases are numerous and important enzymes (see also Chapt. 2). They are classified as phosphoric monoester hydrolases (phosphatases, EC 3.1.3), phosphoric diester hydrolases (phosphodiesterases, EC 3.1.4), triphosphoric monoester hydrolases (EC 3.1.5), diphosphoric monoester hydrolases (pyrophosphatases, EC 3.1.7), and phosphoric triester hydrolases (EC 3.1.8) [21] [63]. Most of these enzymes have a narrow substrate specificity restricted to endogenous compounds. However, some of these enzymes are active toward xenobiotic organophosphorus compounds, e.g., alkaline phosphatase (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2), aryldialkylphosphatase (para-oxonase (PON1), EC 3.1.8.1) and diisopropyl-fluorophosphatase (tabunase, somanase, EC 3.1.8.2) [64 - 70]. However, such a classification is far from definitive and will evolve with further biochemical findings. Thus, a good correlation has been found in human blood samples between somanase and sarinase activities on the one hand, and paraoxonase (PON1) type Q isozyme concentrations on the other [71]. 

---