The disproportionation of zirconium trichloride

Abstract

Equilibrium pressures of the reaction 2ZrCl₃(c) + ZrCl₂(c) + ZrCl₄(g) measured by a cooling curve modification of the dew-point technique are fitted over the range 613-723°K, by the relation        Log₁₀p_mm = -6246/T ? 11.632 ± 0.05 (S.D.). Derived thermochemical data are ΔH₂₉₈ = 30.1 ± 0.5 kcal and ΔS₂₉₈ = 39.1 ± 1 e.u., consistent with estimated ΔHf₂₉₈ZrCl₂ = - 136 kcal/mole and ΔHf₂₉₈ZrCl₂ = -136 kcal/mole, S₂₉₈ZrCl₃ = 36.4 e.u. and S₂₉₈ZrCl₂ = 28.3 e.u.