Infrared spectra have been studied over the range 4000−200 cm-1 for (CH3)2TiCl2, (CD3)2TiCl2, (CH2D)2TiCl2, and (CHD2)2TiCl2 in the gas and matrix phases. Some new spectral observations are also reported for CH3TiCl3 and CD3TiCl3. Equilibrium geometries and force fields are calculated for both Me2TiCl2 and MeTiCl3 using both ab initio (MP2) and DFT approaches. Scale factors for the force fields were first determined in MeTiCl3 and then transferred to Me2TiCl2 so as to provide accurate estimates and facilitate the assignment of the spectra of Me2TiCl2. Quantum mechanical (QM) calculations of infrared intensity proved to be vital in this process. A number of Fermi resonances involving skeletal bending modes below 200 cm-1 are postulated. Combination and overtone evidence for these modes suggests that they occur close to their predicted positions in all cases except one. The infrared evidence from the C−H and C−D stretching regions indicates that the C−H bonds in each methyl group in Me2TiCl2 are equivalent and slightly weaker than those in MeTiCl3. The H−C−H angle in Me2TiCl2 is found to be 109 ± 1°, about 1° less than in MeTiCl3. These results are largely reproduced by the DFT calculations, whereas the ab initio values indicate little difference between the two compounds. The skeletal interbond angles in Me2TiCl2 are particularly sensitive to the type of QM calculation, but all calculations agree on a reduced C−Ti−C and an enlarged Cl−Ti−Cl angle, compared with the tetrahedral value. Problems arising in customary scaling procedures are addressed. The mode of thermal decomposition of the molecule is discussed.