LiCu2O2 crystals grown by spontaneous crystallization from the fluxed melt were studied by powder X-ray diffraction. The phase analysis shows that the applied growth conditions are suitable for preparation of a single-phase compound. The as-grown crystals contain only traces of foreign phases (Li2CuO2, CuO, Cu2O) typical for preparation of the LiCu2O2 compound. Attempts to anneal or quench the as-grown crystals led to two-phase samples containing LiCu2O2 and LiCu3O3. X-ray powder diffraction pattern of a LiCu2O2 crystal is reported and compared with literature data. The crystal structure is orthorhombic, space group Pnma, in agreement with literature data. Lattice parameters of the studied sample are a=5.7286(2) Å, b=2.8588(1) Å, and c=12.4143(3) Å. Time evolution of a diffraction pattern illustrates a slow increase of the secondary-phases contribution assumed to be due to interaction of the powdered crystal with humid air. A brief summary of compounds known in the Li–Cu–O system is included
