Thermal decomposition of lead titanyl oxalate tetrahydrate
Velde van de, G.M.H. and Oranje, P.J.D. (1976) Thermal decomposition of lead titanyl oxalate tetrahydrate. Thermochimica Acta, 14 (3). pp. 269-278. ISSN 0040-6031
|Abstract:||The thermal behaviour of PbTiO(C2O4)2·4H2O (PTO) has been investigated, employing TG, quantitative DTA, infrared spectroscopy and (high temperature) X-ray powder diffraction.
The decomposition involves four main steps. The first is the dehydration of the tetrahydrate (30–180°C), followed by a small endothermic (270–310°C) and a large exothermic decomposition of the oxalate. The main (exothermic) oxalate decomposition (310–390°C) results in a stable oxide-carbonate PbTiO25.(CO3)0.5. In the last step a phase transition, release of CO2 and ordering of the crystalline cubic PbTiO3 lattice can be detected (460–530C).
It can be argued that for thermodynamic reasons the presence of lead-oxo- carbonates in the oxide-carbonate intermediate is not possible.
No differences could be found in thermal behaviour of two crystallographically different synthetic forms of PTO, of which one has an orthorhombic lattice.
|Copyright:||© 1976 Elsevier Science|
|Link to this item:||http://purl.utwente.nl/publications/68350|
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