Phosphorus oxynitride

Other phosphorus-based polymers have been investigated and have proved to be of some interest. An example is phosphorus oxynitride, which forms a glass above 1000°C. 

The solids considered in this section are phosphorus oxynitrides and nitridooxophosphates. They are pentavalent phosphorus(V) compounds and correspond to a partial substitution of nitrogen, under the nitride form N3, for oxygen 02 within P04 tetrahedra, resulting in the formation of mixed P(0, N)4 tetrahedra. 

Following ternary phosphorus oxynitrides, which involve only phosphorus as a cationic element, quaternary and higher oxynitrides will be described. A number of other solid-state PON compounds are under study and, when considering the richness of the phosphate crystal chemistry and the additional degree of freedom given by the presence of nitrogen, it is very probable that many new nitridooxophosphate compositions will be found in the near future. 

Although a chemical substance with the PON formulation was reported as early as 1846 (186), this phosphorus oxynitride was not well known for a long time. That is essentially due to some difficulty in its preparation and to the X-ray amorphous character of the commonly obtained powders. 

Phosphorus oxynitride, PON, is a useful starting product, as a phosphorus and nitrogen source, to prepare various nitridooxophos-phates, in particular phosphorus oxynitride glass compositions (211). Moreover, it shows as a material excellent chemical stability with potential applications in several domains. In microelectronics, for example, PON has been used to form by evaporation insulating films for the passivation of III-V InP substrates and the elaboration of MIS (metal-insulator-semiconductor) structures (190, 212-215). PON could have also valuable properties in flame retardancy (176,191,216). 

Millers and Vitola (217) have mentioned different crystalline phosphorus oxynitride compositions that are located in between PON and... 

To conclude, it is pleasant to consider the regular evolution from 0 to 4 of the number of bridging atoms in the following series of phosphate compounds, which is nicely completed by the phosphorus oxynitride PON (237). 

Arsenic selenide Dickite Phosphorus oxynitride Wollastonite... 

The application of P NMR to structural studies of alkali and alkaline earth phosphate and aluminophosphate glasses, fluorophosphate glasses and phosphorus oxynitride glasses has been reviewed by Kirkpatrick and Brow (1995). 

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