We will probe the response of the 18K superconductor LiFeAa to pressures of up to 2 GPa in order to investigate the evolution of the crystal structure. In particular we wish to use neutron diffraction to locate the Li ion. LiFeAs appears to be much more compressible than other related materials and offers an excellent system on which to probe the effect of structural changes on superconductivity. The results will be compared with high pressure magnetometry measurements and could provide valuable input into computational studies.