Rare-earth chromium citrates as precursors for rare-earth chromites: lanthanum biscitrato chromium(III) dihydrate, La[Cr(C6H5O7)2]·2H

Sujatha, Devi P and Subba, Rao M (1989) Rare-earth chromium citrates as precursors for rare-earth chromites: lanthanum biscitrato chromium(III) dihydrate, La[Cr(C6H5O7)2]·2H. In: Thermochimica Acta, 153 (1). pp. 181-191.

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Abstract

The thermal decomposition of lanthanum biscitrato chromium(III) dihydrate has been studied in static air and dynamic argon atmospheres. The complex decomposes in four steps: dehydration, decomposition of the citrate to an intermediate oxycarbonate, formation of LaCrO4(V) from oxycarbonate, and finally decomposition of LaCrO4(V) to LaCrO3. Formation of LaCrCrO4(V) requires the presence of oxygen The decomposition behaviour of a mechanical mixture of lanthanum citrate hydrate and chromium citrate hydrate was compared with that of the citrato complex. Both the starting material and the intermediates were characterized by X-ray diffraction, IR electronic and ESR spectroscopy, surface area and magnetic susceptibility measurements, as well as by chemical analysis. A scheme is proposed for the decomposition of lanthanum biscitrato chromium(III) dihydrate in air. LaCrO3 can be obtained at temperatures as low as 875 K by isothermal decomposition of the complex.

Item Type:	Journal Article
Publication:	Thermochimica Acta
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	03 Aug 2010 04:50
Last Modified:	19 Sep 2010 06:12
URI:	http://eprints.iisc.ac.in/id/eprint/30960

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