Standard Free Energies for the Formation of Fluorides in Several Metals by Electro-Motive Force Measurements

Abstract

The standard free energies for formation of AlF₃, ThF₄, UF₃, UF₄, CrF₂, MnF₂ and CrF₃ were determined by emf measurements. The following fluorine concentration cells were operated at 600°C:
(This article is not displayable. Please see full text pdf.)
From the emf values and Δ^fG^°(MgF₂) obtained from Δ^fH^° data by calorimetry measurements, the standard free energies of formation of the above fluorides at 600°C were calculated as follows : Δ^fG^°(AlF₃)=−306.0±0.2, Δ^fG^°(ThF₄)=−436.6±0.8, Δ^fG^°(UF₃)=−310.9±0.8, Δ^fG^°(UF₄)=−394.0±1.3, Δ^fG^°(CrF₂)=−156.4±0.3, Δ^fG^°(MnF₂)=−175.0±0.2, Δ^fG^°(CrF₃)=−229.1±1.0. (kcal/mol)