Thermochemical study of vaporization of sodium and potassium perrhenate using a mass spectrometer

Abstract

The vapour phase in equilibrium with sodium perrhenate and potassium perrhenate contains comparable amounts of the corresponding monomeric and dimeric molecules. Partial pressures and heats of vaporization for each of these species were measured: NaReO₄(l)→NaReO₄(g), ΔH^°₇₅₀= 45.3 ± 5 kcal/mole, 2NaReO₄(l)→(NaReO₄)₂(g), ΔH^°₇₅₀= 56.7 ± 5 kcal/mole, KReO₄(s)→KReO₄(g), ΔH^°₇₅₀= 45.8 ± 5 kcal/mole, 2KReO₄(s)→(KReO₄)₂(g), ΔH^°₇₅₀= 65.6 ± 5 kcal/mole.