| Popis: |
Using DSC, TG, EM, quantitative TLC and XRD methods, the iso- and non-isothermal behavior of the sodium chain-triphosphate hexahydrate, Na5P3O10 · 6H2O, has been investigated in vacuum and in flows of different gases. Its specificity and some differences from the thermal behavior of the sodium cyclo-triphosphate hexahydrate, Na3P3O9 · 6H2O, are discussed. On heating, successive processes take place: a dehydration of the Na5P3O10 · 6H2O through a series of steps, involving a degradation step to the mono- and diphosphates, which cannot react with the gaseous ammonia, and their recondensation to Na5P3O10-II; the transition of Na5P3O10-II into Na5P3O10-I, and melting of Na5P3O10-I with anion rearrangement. At premelting and melting stages of Na5P3O10-I, some effects, sensitive to the material of the pan, were observed. These effects have been explained by an unconventional change of physical state and the anion composition of the sample. |
