The results of recent structural studies of some Manganese perovskites are presented, in particular oxides inthe system Cal_xSrxMn03 and SrRllo.sMno.503' In the fIrst series we fIrstly show the power of synchrotron X-ray powderdiffraction to refme accurate and precise structures for oxides containing fIrst row transition metals and then show thepresence of a direct orthorhombic Pbnm to tetragonal 14/mcm transition associated with the tilting of the Mn06octahedra. The inclusion of a heavier second row transition metal reduces the precision of the structure, however thedetails of the tetmgonal to cubic phase transition in SrRllo.sMno.503 are still established.Keywords: Perovskite, Phase Transition, Synchrotron X-ray Powder Diffraction, Jahn- Teller Distortion. B. J. KennedySchool of Chemistry, The University of Sydney, Sydney, NSW 2006 Australia
