Metaphosphate ortho-phosphates

Neodynium ultraphosphate, NdPjO (5.185), is an efficient and much-used laser material. The cyclic tetrametaphosphates MNdP40j2 (M = Li, Na, K), the ortho phosphates M3Nd(P04)2, M = Na, K, fluorapatite doped with Nd + or Ho + and Nd-doped metaphosphate glasses are also efficient laser materials. 

Metavanadates, metaphosphates Ortho- and pyro-vanadates, molybdates, tungstates, chromates, phosphates, etc. 

Elemental composition P 38.73%, H 1.26%, O 60.01%. The compound may be identified by physical properties alone. It may be distinguished from ortho and pyrophosphates by its reaction with a neutral silver nitrate solution. Metaphosphate forms a white crystalline precipitate with AgNOs, while P04 produces a yellow precipitate and P20 yields a white gelatinous precipitate. Alternatively, metaphosphate solution acidified with acetic acid forms a white precipitate when treated with a solution of albumen. The other two phosphate ions do not respond to this test. A cold dilute aqueous solution may be analyzed for HPO3 by ion chromatography using a styrene divinylbenzene-based low-capacity anion-exchange resin. 

The tribofilms consist of amorphous, short-chain phosphates (ortho- and metaphosphates), with some evidence of sulfur incorporated into the phosphate chain structure. Tribofilm structure depends not only on the lubricant composition of the substrate material, but also on the severity of the rubbing contact. The ZDDP typically forms phosphates under antiwear conditions, whereas sulfides and sulfates are typically formed under severe or very severe conditions, li > 0.8 (Willermet et al., 1997). 

Uranyl Phosphates.—Well-defined ortho- and pyro-phosphates exist, but little is known of uranyl metaphosphate. Several complex uranyl phosphates have been described. 

J. J. Berzelius was first to class phosphates by their M2O-P2O5 ratio while Thomas Graham was first to classify phosphates as ortho-, pyro-, and metaphosphates in 1833. He recognized that they suffered from hydrolytic degradation or hydrolysis back to orthophosphates. For example ... 

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