Lithiated spinel manganese oxides with various amounts of lithium have been prepared through solid-state reaction and electrochemical intercalation and deintercalation. Structures of the LixMn2O4samples with 0.3≤x≤1.2 are studied using X-ray diffraction and Rietveld refinement techniques. We report vibrational spectra of lithiated manganese oxides as a function of lithium concentration. The spectra of lithiated spinel manganese oxides have been analyzed on the basis of LiO4tetrahedra and MnO6octahedra when Li/Mn≤0.5, and LiO4, LiO6, and MnO6structural units when Li/Mn>0.5. Electrochemical performances of lithium manganese oxide are also studied.