Formation enthalpies and heat capacities of rear earth titanates: RE 2TiO 5 (RE=La, Nd and Gd)

Shmuel Hayun; Alexandra Navrotsky

doi:10.1016/j.jssc.2011.12.033

Formation enthalpies and heat capacities of rear earth titanates: RE ₂TiO ₅ (RE=La, Nd and Gd)

Shmuel Hayun, Alexandra Navrotsky

Department of Materials Engineering

Research output: Contribution to journal › Article › peer-review

30 Scopus citations

Abstract

The formation enthalpies and heat capacities of orthorhombic rare earth titanates, RE ₂TiO ₅ (RE=La, Nd and Gd), have been studied by high temperature differential scanning calorimetry (3001473 K) and oxide-melt solution calorimetry. The RE ₂TiO ₅ samples are stable in enthalpy with respect to their oxides and the pyrochlore RE ₂Ti ₂O ₇ phase. The general trend that has been demonstrated in other RE-ternary systems; decreasing thermodynamic stability with decreasing R _A/R _B was found to be valid for the RE ₂TiO ₅, and their enthalpies of formation from oxides become more negative with increasing RE ³ ionic radius.

Original language	English
Pages (from-to)	70-74
Number of pages	5
Journal	Journal of Solid State Chemistry
Volume	187
DOIs	https://doi.org/10.1016/j.jssc.2011.12.033
State	Published - 1 Mar 2012

Keywords

Formation enthalpy
Heat capacity
Rear earth titanates

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Condensed Matter Physics
Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

Access to Document

10.1016/j.jssc.2011.12.033

Cite this

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title = "Formation enthalpies and heat capacities of rear earth titanates: RE 2TiO 5 (RE=La, Nd and Gd)",

abstract = "The formation enthalpies and heat capacities of orthorhombic rare earth titanates, RE 2TiO 5 (RE=La, Nd and Gd), have been studied by high temperature differential scanning calorimetry (3001473 K) and oxide-melt solution calorimetry. The RE 2TiO 5 samples are stable in enthalpy with respect to their oxides and the pyrochlore RE 2Ti 2O 7 phase. The general trend that has been demonstrated in other RE-ternary systems; decreasing thermodynamic stability with decreasing R A/R B was found to be valid for the RE 2TiO 5, and their enthalpies of formation from oxides become more negative with increasing RE 3 ionic radius.",

keywords = "Formation enthalpy, Heat capacity, Rear earth titanates",

author = "Shmuel Hayun and Alexandra Navrotsky",

note = "Funding Information: This work was supported by the U.S. National Science Foundation (grant DMR-09-06344 ). Shmuel Hayun would like to thank the International Sephardic Education Foundation (ISEF) for the Postdoctoral Fellowship. ",

year = "2012",

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doi = "10.1016/j.jssc.2011.12.033",

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T2 - RE 2TiO 5 (RE=La, Nd and Gd)

AU - Hayun, Shmuel

AU - Navrotsky, Alexandra

N1 - Funding Information: This work was supported by the U.S. National Science Foundation (grant DMR-09-06344 ). Shmuel Hayun would like to thank the International Sephardic Education Foundation (ISEF) for the Postdoctoral Fellowship.

PY - 2012/3/1

Y1 - 2012/3/1

N2 - The formation enthalpies and heat capacities of orthorhombic rare earth titanates, RE 2TiO 5 (RE=La, Nd and Gd), have been studied by high temperature differential scanning calorimetry (3001473 K) and oxide-melt solution calorimetry. The RE 2TiO 5 samples are stable in enthalpy with respect to their oxides and the pyrochlore RE 2Ti 2O 7 phase. The general trend that has been demonstrated in other RE-ternary systems; decreasing thermodynamic stability with decreasing R A/R B was found to be valid for the RE 2TiO 5, and their enthalpies of formation from oxides become more negative with increasing RE 3 ionic radius.

AB - The formation enthalpies and heat capacities of orthorhombic rare earth titanates, RE 2TiO 5 (RE=La, Nd and Gd), have been studied by high temperature differential scanning calorimetry (3001473 K) and oxide-melt solution calorimetry. The RE 2TiO 5 samples are stable in enthalpy with respect to their oxides and the pyrochlore RE 2Ti 2O 7 phase. The general trend that has been demonstrated in other RE-ternary systems; decreasing thermodynamic stability with decreasing R A/R B was found to be valid for the RE 2TiO 5, and their enthalpies of formation from oxides become more negative with increasing RE 3 ionic radius.

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