ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Dehydration of  GdPQ₄ • xH₂0

I. Horváth, L. P Mezentseva, and V. Figusch

Institute of Inorganic Chemistry, Slovak Academy of Sciences, 809 34 Bratislava

Abstract: Dehydration and rehydration of hexagonal GdPO₄ hydrate  were studied by TG and DSC. Water mols. are bound in 2 energetically different levels. The 1st step of dehydration ends at 100°, and the 2nd takes place at 170-230°. The 1st step corresponds to the release of H₂O mols. weakly bound on the surface of crystals and in the pores (hygroscopic water). During the 2nd step, the mols. in channels of the skeletal structure of GdPO₄ are released. The dehydration is reversible at 170-230°. The enthalpy changes of the 1st and 2nd steps are nearly the same (44.7 and 47.7 kJ/mol, resp.). The amt. of water released in the 2nd step is characteristic for a particular orthophosphate.

Full paper in Portable Document Format: 353a333.pdf

Chemical Papers 35 (3) 333–338 (1981)