DISPROPORTIONATION, VAPORIZATION, AND ENT HALPY OF FORMATION OF LOWERCHLORIDES OF TITANIUM

Using the static method, we have measured the saturated vapor pressure above samples of original composition TiCl3 and the system of solid s olutions of TiCl2.93 and TiCl2.42log P(TiCl4), atm = -8084/T + 8.725 ( 735-912 K), confirmed by effusion measurements with mass spectrometric analysis of the composition of the vapor logP(TiCl4), atm = -8824/T 9.693 (533-620 K). We have determined the equilibrium constants and c alculated the enthalpies of reaction at 298 K (kJ/mole): Ti(c) + 3/4Ti Cl = TiCl + 47.4; 1/2TiCl2c + 1/2TiCl4 = TiCl3 + 107.0 and 1/2TiCl2 1/2TiCl4 = TiCl3 - 15.7. On the basis of the data obtained the literat ure data, we recommend the following enthalpies of formation at 298 K: gaseous TiCl3 - 530.2 +/- 2.3; TiCl2 - 261.8 +/- 3.4; and TiCl - 152. 2 +/- 15 kJ/mole.