Gaseous Metal Nitrides. IV. The Dissociation Energy of Cerium Mononitride

The CeN molecule has been identified in the vapor phase over a Au–Ce–CeS–BN–C mixture, using a combination of Knudsen effusion and mass spectrometric techniques. The third law enthalpies for the reactions 2CeN(g)=N2(g)+Ce2(g), 2CeN(g)+Au2(g)=2CeAu(g)+N2(g), 2CeN(g)=2Ce(g)+N2(g), and 2CeN(g)+2Au(g)=2CeAu(g)+N2(g) were determined. Combined with published ancillary data, these reaction enthalpies yielded the following thermodynamic properties for gaseous CeN: CeN(g)=Ce(g)+N(g); D0° = 123.0 ± 5.0 kcal mol−1 or 514.6 ± 21 kJ mol−1 Ce(s)+0.5 N2(g)=CeN(g); ΔHf,298° = 90.1 ± 4.0 kcal mol−1 or 377.0 ± 17 kJ mol−1.