Hydrothermal phase equilibria in Ln2O3-H2O-CO2 systems for Tm, Yb and Lu

Kuttya, TRN and Mohamed, Iftiqhar and Tareen, JAK (1984) Hydrothermal phase equilibria in Ln2O3-H2O-CO2 systems for Tm, Yb and Lu. In: Materials Chemistry and Physics, 10 (5). pp. 425-441.

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Abstract

Phase diagrams for Tm2O3-H2O-CO2. Yb2O3-H2O-CO2 and Lu2O3-H2O-CO2 systems at 650 and 1300 bars have been investigated in the temperature range of 100–800°C. The phase diagrams are far more complex than those for the lighter lanthanides. The stable phases are Ln(OH)3, Ln2(CO3)3.3H2O (tengerite phase), orthorhombic-LnOHCO3, hexagonal-Ln2O2CO3. LnOOH and cubic-Ln2O3. Ln(OH)3 is stable only at very low partial pressures of CO2. Additional phases stabilised are Ln2O(OH)2CO3and Ln6(OH)4(CO3)7 which are absent in lighter lanthanide systems. Other phases, isolated in the presence of minor alkali impurities, are Ln6O2(OH)8(CO3)3. Ln4(OH)6(CO3)3 and Ln12O7(OH)10,(CO3)6. The chemical equilibria prevailing in these hydrothermal systems may be best explained on the basis of the four-fold classification of lanthanides.

Item Type:	Journal Article
Publication:	Materials Chemistry and Physics
Publisher:	Elsevier Scince
Additional Information:	Copyright for this article belongs to Elsevier Science.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	30 Jan 2010 05:33
Last Modified:	19 Sep 2010 05:44
URI:	http://eprints.iisc.ac.in/id/eprint/22975

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