Abstract:The formation of the tetragonal high-pressure structure, attributed to the Jahn-Teller distortion, was proved. The c/a ratio shows a trend towards a stronger tetragonal distortion at high pressure. Rietveld refinement after the pressure relaxation shows the presence of tetragonal artefacts of high-pressure structure only for LiMn 2 O 4 sample compressed in h-BN, whereas the sample compressed in silicone reveal the pure cubic phase. Confrontation with result of the first angledispersive diamond-anvil-cell experiment is presented.