Mass Spectrometric Determination of the Dissociation Energy of EuC2(g)

The vapor phase in equilibrium with condensed europium dicarbide and graphite has been investigated by the Knudsen effusion‐mass spectrometric technique over the temperature range 1800–2320°K. In addition to europium atoms, the dicarbide molecule EuC2(g) was identified and its bond and atomization energies were determined: D0 ° (Eu−C2)=129 ± 5 kcal/mole and Δ H0, atom ° (EuC2)=271 ± 4 kcal/mole.