Solid Reaction of Zinc-Chromium Spinel.

Electronic structure of spinel oxides: zinc aluminate and zinc gallate

The electronic structure of zinc aluminate (ZnAl2O4) and that of zinc gallate (ZnGa2O4) were studied by the self-consistent tight-binding linearized muffin-tin orbital method with the atomic sphere approximation. The calculated results predict these zinc-based spinel oxides to be direct-gap materials. The direct gap at 0 is found to be 4.11 eV for ZnAl2O4 and 2.79 eV for ZnGa2O4. With reference...

Oxygen, magnesium and chromium isotopic ratios of presolar spinel grains

Oxygen isotopic measurements of 20 spinel (MgAl2O4) grains from the CM2 meteorite Murray (average diameter 0.45 m), seven spinel grains from ordinary chondrites (OC, 0.3 to 2 m) and three spinel grains from the CI chondrite Orgueil (0.4 to 0.7 m) have revealed large anomalies and thus established their presolar origin. Their O isotopic ratios fall into all four previously defined groups and ind...

Cation distributions and thermodynamic properties of binary spinel solid solutions

A general model is presented to enable the calculation of the cation distribution and thermodynamic properties of any binary solid solution between oxide spinels containing 2*, 3* and 4* cations. The model includes the effect ofdisordering enthalpy which depends linearly on the degree of disorder. In addition there are important contributions to the thermodynamic properties from the size mismat...

Atomistic Simulation Study of Spinel Oxides: Zinc Aluminate and Zinc Gallate

Stoichiometric zinc aluminate (ZnAl2O4) and zinc gallate (ZnGa2O4) are simulated in the framework of the shell model, for which a new set of two-body interatomic potential parameters has been developed. Using these parameters, a reasonable prediction is made for elastic and dielectric constants of ZnAl2O4 and ZnGa2O4. Both oxides are stable against decomposition to the component oxides. The fit...

Copper , Zinc , Nickel and Chromium Uptake