Compositional and structural investigations of highly stoichiometric titanium disulfide

Highly stoichiometric TiS 2 has been studied chemically, structurally, magnetically, and thermogravimetrically. Ammonia intercalation rate, X-ray diffraction and magnetic susceptibility measurements indicate the stoichiometry of the TiS 2 is essentially identical to the most stoichiometric TiS 2 that has been prepared previously. High-precision thermogravimetric analysis up to 900°C indicates that the actual composition is Ti 1.0032S 2. Residual sulfur analysis yields the corrected formulation Ti 1.0025S 2, which explains the origin of the relatively high conduction-electron density in this extrinsic semiconductor. An anomalous inflection is observed in the thermogravimetric oxidation of TiS 2 to TiO 2 at 620±6°C. X-ray powder diffraction patterns of samples cooled rapidly at temperatures between 360 and 900°C reveal that anatase and rutile are the only crystalline phases present. It is suggested that the inflection at 620°C may be due to interfacial changes associated with the onset of the anatase-to-rutile phase transition.