ChemInform Abstract: Synthesis, Symmetry, and Physical Properties of Cerium Pyrophosphate

Autor:	William A. Bassett, Andrew C. Jupe, E. A. Payzant, K. M. White, C.-S. Zha, Peter J. Chupas, Karena W. Chapman, Angus P. Wilkinson, Peter L. Lee
Rok vydání:	2008
Předmět:	Diffraction Cerium Bulk modulus Phase transition Chemistry Phase (matter) Analytical chemistry chemistry.chemical_element General Medicine Triclinic crystal system Oxygen Thermal expansion
Zdroj:	ChemInform. 39
ISSN:	1522-2667 0931-7597
Popis:	CeP2O7, a close structural relative of ZrP2O7, and many other MIVX2O7 (X – P, V, As) phases, forms on heating Ce(HPO4)2·xH2O between ∼300 and 600 °C and decomposes by oxygen loss at higher temperatures. In-situ X-ray diffraction measurements showed, for some precursor batches, the formation of CeP2O7 in two distinct stages. At room temperature, CeP2O7 is pseudocubic, but probably triclinic, displaying positive thermal expansion below ∼115 °C. Above this temperature, there is a transition to cubic symmetry (Pa3) with the linear coefficient of thermal expansion going to zero at ∼450 °C and becoming negative at higher temperatures. CeP2O7 probably undergoes two phase transitions on compression below ∼10.5 GPa. The phase existing between 0.65 and ∼5 GPa is soft with an average bulk modulus of ∼18 GPa.
Databáze:	OpenAIRE
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