Thermodynamic study of sodium–iron oxides

Vaporization behavior of Na4FeO3(s) was thermodynamically studied from 590 to 717 K by means of high temperature mass spectrometry. It was found that Na4FeO3(s) decomposed into Na3FeO3(s) and released sodium vapor. The temperature dependence of partial vapor pressure of sodium over Na4FeO3(s) was measured so that the Gibbs energy of formation of Na3FeO3(s) was evaluated as ΔfG°(Na3FeO3)=−1168629+338.34×T.