We propose to study the structure of liquid CO2 by neutron diffraction under high pressure and high temperatures to 6 GPa / 800 K. Carbon dioxide belongs to the most fundamental molecular systems known. The presence of a molecular quadrupole terms is expected to lead to strong orientational correlations with the formation of ¿T-shaped¿ CO2 dimers predicted by molecular dynamics simulations. Previously granted beamtime has allowed to develop the techniques and to collect preliminary data up to 2 GPa which show the feasibility of such a study. The data analysis will be carried out using the EPSR algorithm similar to our previous study on hot dense liquid water (PRL 96, 067801 (2006)).