Heat of Formation of Titanium Tetraiodide

The heat of formation of titanium tetraiodide was determined relative to that of titanium tetrabromide by comparison of their heats of hydrolysis in dilute sulfuric acid. The difference in the heats of formation may be expressed by the equation: [Formula: see text] By taking the heat of formation of TiBr(4)(c) as −616.72 ±4.60 kj/mole, the heat of formation of TiI(4)(c) is calculated to be −385.81 ±4.64 kj/mole (−91.21 ±1.11 kcal/mole). The heats of hydrolysis of TiBr(4) and TiCl(4) were similarly measured; the value obtained for the difference (186.77 ±1.34 kj/mole) is in good agreement with the difference between the directly determined heats of formation (187.11 ±5.35 kj/mole).