Thermochemical properties of gaseous FeO and FeOH

The dissociation energy of FeOH, D00(Fe–OH), has been measured mass spectrometrically by passing H2O(g) and H2(g) over Fe2O3 in a Knudsen cell. The measurements lead to D00(Fe–OH)=76.9±4 kcal/mol (3.3±0.2 eV). The ionization potential of FeOH was measured and found to be 7.9±0.2 eV. An equilibrium involving gaseous FeO was also measured and the results of this study together with an analysis of previous data lead to D00(FeO)=93.0±3 kcal/mol (4.03±0.13 eV). The following data were derived from the measurement: D00(Fe+–O)=3.15±0.2 eV, D00(Fe+–OH)=3.3±0.2 eV, D00(FeO+–H)=4.7±0.2 eV, and PA(FeO)=D00(FeO–H+)=9.40±0.2eV. The similarity in bonding between D00(Fe–OH) and D00(Fe–Cl) is briefly discussed.