Complex transition-metal oxyfluorides prepared via topochemical manipulation

Topochemical fluorination of A3B2O7, n = 2 Ruddlesden-Popper oxides yields phases of composition A3B2OxFy (5≤x≤7, 2≤y≤4, x+y = 9). The synthesis of these phases has been shown to occur via both the intercalation of F- in the rocksalt layers of the host phases and partial substitution of ‘framework’ oxide ions. Subsequent reduction of these oxyfluorides using LiH yields phases with anionic contents varying from O5F4 to O4F2, none of which can be prepared directly via conventional ceramic synthesis. We propose to collect neutron powder diffraction data from a series of LaSr3CoRuOxFy and La3Ni2OxFy phases to determine the crystal and magnetic structures.