Rietveld refinements of X-ray data of LiCoO2 prepared at 400-degrees-C and a chemically-delithiated product Li0.5CoO2 using space group symmetries R3mBAR and Fd3m are reported. Refinements in both R3mBAR (layered-type structure) and Fd3m (spinel-type structure) give comparable fits to the data. This structural anomaly is discussed in terms of the refinements and electrochemical data obtained when lithium is extracted from LiCoO2 in non-aqueous cells at room temperature. A spinel-related model for LixCoO2 (0.5 less-than-or-equal-to x less-than-or-equal-to 1) is preferred.