Enthalpy of formation of CaSi2O5, a quenched high-pressure phase with pentacoordinate silicon

M. Schoenitz, A. Navrotsky, N. Ross

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The monoclinic titanite-like high-pressure form of calcium disilicate has been synthesized and quenched to ambient conditions to form the triclinic low-pressure phase containing silicon in four-, five- and sixfold coordination. The enthalpy of formation of the quench product has been measured by high-temperature oxide melt calorimetry. The value obtained from samples from a series of several synthesis experiments is △Hf = (-26.32 ± 4.27) kJ mol-1 for the formation from the component oxides, or △Hf = (-2482.81 ± 4.59) kJ mol-1 for the formation from the elements. The result is identical within experimental error to available estimates, although the previously predicted energy difference between the monoclinic and triclinic phases could not be verified.

Original languageEnglish (US)
Pages (from-to)57-60
Number of pages4
JournalPhysics and Chemistry of Minerals
Volume28
Issue number1
DOIs
StatePublished - Aug 7 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Geochemistry and Petrology

Keywords

  • Calcium disilicate
  • Fivefold coordination
  • Oxide melt calorimetry
  • Pentacoordinate silicon
  • Phase transition

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