Ammonium pyrophosphates

A large number of pyrophosphate salts have been prepared (Table 10). In addition to individual metal salts, ammonium pyrophosphates and many mixed-metal pyrophosphates are known. Pyrophosphates of notable commercial importance include sodium, potassium, and calcium salts. 

Delobel, R., Le Bras, M., Ouassou, N., and Alistiqsa, F. 1990. Thermal behaviors of ammonium polyphosphate-pentaerythritol and ammonium pyrophosphate-pentaerythritol intumescent additives in polypropylene formulations. J. Fire Sci. 8 85-92. 

Ammonium pyrophosphates.—Excess of ammonia reacts with pyrophosphoric acid to form normal ammonium pyrophosphate, (NH4)4P207, precipitated from aqueous solution by addition of alcohol. It forms crystalline laminae, dissolving very readily in water to a solution of alkaline reaction.7 When boiled, this solution evolves ammonia, yielding am acid solution of secondary ammonium pyrophosphate, (NH4)2H2P207. 

A variety of crystals may be present in the urine, including uric acid, calcium oxalate, calcium phosphate, calcium magnesium ammonium pyrophosphate, and cystine. Many of these have a unique crystalline form which permits them to be identified with microscopy. 

CAS 10101-66-3 EINECS/ELINCS 233-257-4 Synonyms Ammonium manganese pyrophosphate Cl 77742 Diphosphoric acid, ammonium manganese (3+) salt (1 1 1) Manganese ammonium pyrophosphate Pigment violet 16 Classification Inorganic salt Empirical H4O7P2 H N Mn Toxicology TSCA listed... 

Manganese ammonium pyrophosphate. See Manganese violet Manganese aspartate CAS 16351-10-3... 

Where specification of the metal is considered to be important, polarographic analysis may be utilized. In the case of primers based on oil-soluble iron salts for use with anaerobic adhesives, the Fe /Fe ratio may be determined by differential pulse polarography in a supporting electrolyte based on ammonium pyrophosphate buffer adjusted to pH 9.0. The iron(II) form is known to be significantly more effective than the iron(III) form in the redox-based curing process. 

Ammonium pyrophosphates are obtained by passing ammonia into pyrophosphoric acid below 10°C. Precipitation with alcohol at 0°C and pH 6.5 gives crystalline (NH4)4P207 H2O, and the anhydrous compound at 25°C, both of which slowly lose ammonia to the atmosphere. 

Cobalt orthojiiosphate Manganese ammonium pyrophosphate Zinc phosphate Lead phosphates... 

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