Enthalpy of Formation of Zircon

Adam J.G. Ellison, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

Using high‐temperature solution calorimetry in molten 2PbO. B2O3, the enthalpy of reaction of the formation of zircon, ZrSiO4, from its constituent oxides has been determined: ΔrH977(ZrSiO4) =−27.9 (± 1.9) kJ/mol. With previously reported data for the heat contents of ZrO2, SiO2, and ZrSiO4 and standard‐state enthalpies of formation of ZrO2 and SiO2, we obtain Δf298· (ZrSiO4) =−2034.2 (±3.1) kJ/mol and Δf298 (ZrSiO4) =−1919.8 kJ/ mol. The free energy value is in excellent agreement with a range previously estimated from solid‐state reaction equilibria. At higher temperature also the data are in close agreement with existing data, though the data sets diverge somewhat with increasing T. The limitations of the data for predicting the breakdown temperature of zircon into its constituent oxides are discussed.

Original languageEnglish (US)
Pages (from-to)1430-1433
Number of pages4
JournalJournal of the American Ceramic Society
Volume75
Issue number6
DOIs
StatePublished - Jun 1992
Externally publishedYes

Keywords

  • enthalpy
  • formation
  • free energy
  • oxides
  • zircon

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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