This proposal is concerned with determining variations in the high pressure structure of LaCoO3 and observing changes within this as the material undergoes some well characterised temperature-driven electronic transitions. By driving LaCoO3 through the well known spin state transitions by pressure we aim to:a) An understanding of the Co-O bond distance and spin states as a function of pressure.b) Determine the variation in the octahedral tilting of the CoO6 octahedra as a function of pressure.c) Derive insight into the structural variation, transition temperatures and pressures at the LS-IS-HS transitions – significantly enhancing knowledge of the phase diagram of this important compound.This information is crucial for understanding the nature of spin-state transitions and related phenomena in RCoO3 cobaltates in general.