Structure Refinement of Quaternary Spinel Oxides - Experiments and Modelling

Comprehensive studies have been undertaken, inclusive of experimental and computational techniques, on the structure and cation distribution of spinel solid solutions formed between the normal spinel LiMn2O4 and inverse LiFe5O8. Series of solid solutions of a composition (1 - x)LiMn2O4 x xLi0.5Fe2.5O4 are single phase products with spinel structure in the whole range of x, displaying a cubic structure. With increasing Fe3+ content, the tendency of ordering by lithium ions in octahedral spinel sites and a strongly marked preference of Li+ cations to occupy the octahedral positions is apparent. Modelling and refinement of crystal structure of such spinel solid solution series have been undertaken by the energy minimisation procedure, together with the interatomic potentials calculation, explaining some divergences of the experimental data.