Some Thermodynamic Properties of Indium Trichloride, Indium Hydroxide, and Indium Trioxide

The equilibrium diagram of the system InCl3–H2O as been determined as far as it can be followed. From these freezing points, the activity coefficients at the freezing temperatures have been calculated. The heats of solution and of dilution of hydrated and of anhydrous indium chloride, in water, have been determined, as well as the heats of solution of indium hydroxide and of indium oxide (In2O3) in concentrated hydrochloric acid. From these data, the heat of the reaction: 2In(OH)3 = In2O3 + 3H2O and the molar enthalpies of InCl3 and In(OH)3 have been calculated.