Читать книгу Encyclopedia of Glass Science, Technology, History, and Culture - Группа авторов - Страница 267

In P₂O₅ glass, the P─O bridging bond distance (1.60 Å) is nearly identical to the Si─O distance in SiO₂ glass (1.62 Å). Additionally, there is a second double‐bonded and shorter (1.43 Å) P=O bond. These structural features remain for glasses in the P₂O₅–SiO₂ system. In the latter, Si–O–P bridges can also be detected.

Phosphorus in metal oxide silicate and aluminosilicate glasses and melts is dissolved by formation of phosphate (PO₄) groups. Their degree of polymerization can be derived from ³¹P NMR spectra as a function of metal oxide/P₂O₅ ratio [13] in a way similar to Q ⁿ ‐species determinations in metal oxide–SiO₂ glasses (see also Chapter 2.4 and Section 3.1). In addition, there are minor contributions from Si─O─P linkages. Mixed alumino‐silico phosphate complexes are more common (Chapter 2.4).