Ultraphosphates formation

Above 410 C the ultraphosphate undergoes a relatively slow degradation process which is completed at about 650 C with formation of a residue (35% of original phosphate) mostly stable to 950 C... 

Interaction between bismuth(iii) oxide and phosphoric acid leads to the formation of the orthophosphate as the stable species up to 190 °C, but at temperatures between 200 and 230 °C a tetrapolyphosphate is formed. Compounds obtained at higher temperatures from 4 1 and 5 1 mixtures of P2O5 and Bi203 may be ultraphosphates. 

There is no question whether or not cross-linking is a necessary part of a system with an ultraphosphate composition. It is a structural-composition requirement, but where does cross-linking reside in potassium Kurrol s salt crystallized in ultraphosphate melts Are cross-links contained in crystalline phases and cause the formation of crystalline potassium ultraphosphates, or does a salt obey its phase diagram for a two-component K2O-P2O5 system (See Figure 3.1.)... 

Tetravalent cerium behaves exceptionally upon heating with H3PO4. With low P/Ce ratio (1-3) it forms diphosphate, CePjO, and with a higher proportion of phosphorus it forms catena-polyphosphate, Ce(P03)4. Cerium may also reduce to trivalent in this system, with the formation of Ce(P03)3 at lower temperatures and the ultraphosphate CeP50j4 at higher temperatures (Tsuhako et al., 1979). 

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