Enthalpy of formation of katoite Ca3Al2[(OH)4]3: Energetics of the hydrogarnet substitution

Mirko Schoenitz, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The silicon-free end member of the hydrogrossular solid solution series, katoite Ca3Al2[(OH)4]3, was synthesized in a solid-media, piston-cylinder apparatus. The enthalpy of formation from the component oxides was measured by high-temperature oxide melt calorimetry and found to be ΔH(f) = -255.6 ± 12.2 kJ/mol; the resulting enthalpy of formation from the elements is ΔH(f) = -5551.5 ± 16.4 kJ/mol. From this value, enthalpies for breakdown reactions of hydrogrossular were calculated and the relative energetic stability of katoite evaluated.

Original languageEnglish (US)
Pages (from-to)389-391
Number of pages3
JournalAmerican Mineralogist
Issue number3
StatePublished - Mar 1999
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology


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