Abstract
The pseudobrookite-type compound karrooite (MgTi2O5) has been studied to understand how cation disordering, coupled with tight constraints of symmetry, affects its structural and thermodynamic properties and to address the kinetics of ordering. An empirical model that determines the degree of cation disorder from the c lattice parameter, along with the enthalpy data, has allowed assessment of various thermodynamic models of disordering. A sigmoidal change in lattice parameters with increasing quench temperature results from slow ordering at T < 973 K and from unquenchable cation distributions (ie, extremely rapid ordering) at T > 1273 K. The activation energy of ordering at T < 973 K is 212 ± 10 kJ/mol. -from Authors
Original language | English (US) |
---|---|
Pages (from-to) | 902-912 |
Number of pages | 11 |
Journal | American Mineralogist |
Volume | 74 |
Issue number | 7-8 |
State | Published - 1989 |
Externally published | Yes |
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology