Bismuth and iron/nickel substitution in lanthanum manganese oxide yields materials showing mixed ionic-electronic conductivity and are being investigated as cathode materials for solid oxide fuel cells. While low levels of substitution by bismuth and iron or nickel yield a structure of apparent rhombohedral symmetry, detailed investigation by transmission electron microscopy shows two different crystallite types. At higher levels of substitution an orthorhombic symmetry is adopted with evidence of diffuse scattering, characteristic of local ordering. The present proposal seeks to clarify this phase behavior through a combination of high-resolution neutron diffraction and a total neutron scattering study of oxide ion distribution and local ordering in these systems.