Thermodynamics of the magnetite-ulvöspinel (Fe3O 4-Fe2TiO4) solid solution

Kristina I. Lilova, Carolyn I. Pearce, Christopher Gorski, Kevin M. Rosso, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


The thermodynamics of mixing and its dependence on cation distribution in the Fe3O4-Fe2TiO4 (magnetite-ulvöspinel) spinel solid solution were studied using high-temperature oxide melt solution calorimetry and a range of structural and spectroscopic probes. The enthalpies of formation of ilmenite and ulvöspinel from the oxides and from the elements were obtained using oxidative drop solution calorimetry at 973 K in molten sodium molybdate. The enthalpy of mixing, determined from the fit to the measured enthalpies of drop solution calorimetry, is endothermic and represented by a quadratic formalism, δHmix = (22.60 ± 8.46)x(1 - x) kJ/mol, where x is the mole fraction of ulvöspinel. The entropies of mixing are more complex than those for a regular solution and have been calculated based on average measured and theoretical cation distributions. Calculated free energies of mixing show evidence for a solvus at low temperature in good agreement with that observed experimentally.

Original languageEnglish (US)
Pages (from-to)1330-1338
Number of pages9
JournalAmerican Mineralogist
Issue number8-9
StatePublished - 2012
Externally publishedYes


  • Calorimetry
  • Enthalpies of mixing
  • Magnetite-ulvö spinel solid solution
  • Titanomagnetite

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology


Dive into the research topics of 'Thermodynamics of the magnetite-ulvöspinel (Fe3O 4-Fe2TiO4) solid solution'. Together they form a unique fingerprint.

Cite this