Thermo-Raman studies on dehydration of Na3PO4 center dot 12H(2)O

In this work, dehydration of Na3PO4. 12H(2)O has been studied dynamically i n detail by thermo-Raman spectroscopy. The dehydration was observed in the temperature range from 30 to 200 degreesC. Spectral variation could disting uish six characteristic spectra of different hydrated species. The thermo-R aman intensity for the stretching bands of H2O showed four distinct steps o f dehydration with Na3PO4. 12H(2)O, Na3PO4. 8H(2)O, Na3PO4. 7H(2)O, Na3PO4. 6H(2)O and Na3PO4.0.5H(2)O as the compositional species. The differential thermo-Raman intensity thermogram indicated the possibility of the existenc e of a new hydrated intermediate species Na3PO4.H2O during the dehydration. The first four steps of dehydration occurred below 84 degreesC and the las t step of loosing 0.5 H2O could not be detected. The results of TG measurem ent showed only two stages of dehydration. (C) 2001 Elsevier Science B.V. A ll rights reserved.