The synthesis of phases of composition Sr7Mn4O15−x 0 < x < 3 was reported via the topotactic manipulation of the anion lattice of Sr7Mn4O15. In addition the reduced, cation substituted phases BaSr6Mn4O13 and Sr6CaMn4O13 were described. Structural characterisation using powder X-ray and neutron diffraction data reveals that in all phases anions were selectively removed from sites which link the MnO6 octahedra in the structure in an apex-sharing manner. An explanation based on the total lattice energy of the anion deficient phases was presented to account for this unusual selectivity.

Anion Vacancy Ordering in Sr7Mn4O15−x Phases. M.O’Malley, M.A.Lockett, M.A.Hayward: Journal of Solid State Chemistry, 2007, 180[10], 2851-8