P4O10 P2O5 , The Mother of All Condensed Phosphates

Depolymerization of phosphates is unidirectional in aqueous environments, with the exception of some biological systems that convert ADP and orthophosphates back to ATP, etc. Soluble silicates can be polymerized to silica gels or Si02 from aqueous solutions, while sparingly soluble (insoluble) silicates are usually highly refractory. These behaviors of silicates can complicate a study of these systems compared to similar phosphate systems. 

A second approach is to use a more conventional melt chemistry to grow fibers. Conventional high-temperature phosphate melts are not easily contained. Melts of condensed phosphates have been called the Universal Solvent. There are few if any substances they will not dissolve in phosphate melts at higher temperatures. 

In laboratory studies platinum, gold, or some forms of ceramics can be used to contain phosphates while they are heated to melts. Platinum is less attacked by basic melts, while gold is superior for melts rich in P2O5. In all cases at temperatures above 300 °C crucible corrosion contaminates products to a greater or lesser extent, but contamination can very often be localized to areas of contact between crucibles and melts. Larger melts have smaller surface-to-volume ratios. Purer products are manufactured in these cases. This is one reason why a compound can very often be obtained with higher purity from an industrial process than it can be prepared in a laboratory. This is particularly true with compounds such as NasPaOio, which is prepared in large volumes industrially. 

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