The topotactic oxidation in air at room temperature of the lithium titanate bronze LixTiO2 (x = 0.5) crystals with the ramsdellite-type structure leads to lower x values and decreased unit-cell-volumes. The crystal structures of the three specimens, Li0.41TiO2, Li0.16TiO2, and Li0.14TiO2, have been determined by the single-crystal X-ray diffraction method. The deintercalation of lithium in LixTiO2 with 0 ≤ x < 0.5 has been investigated by difference-Fourier maps at z = 1/4 sections. The complete oxidation of parent bronze crystals using an acidic solution obtained colorless crystals of a new polymorph of titanium dioxide, TiO2(R). It crystallizes in the orthorhombic ramsdellite-type structure, in the same space group Pbnm with a = 4.9022(14) Å, b = 9.4590(12) Å, c = 2.9585(14) Å, V = 137.18(7) Å3, Dx = 3.87 g/cm3, Dm = 3.80 g/cm3, and Z = 4. The TiO2(R) structure was also refined from the single-crystal X-ray study to the conventional values R = 0.049 and wR = 0.044 for 596 independent reflections. When heated above 640 K, TiO2(R) transforms into brookite-type TiO2. DTA and IR data of TiO2(R) are measured.