THERMOCHEMICAL PROPERTIES OF GASEOUS LI3O AND LI2O2

Besides LiO and Li2O, the gaseous species Li2O 2 and Li3O were observed by mass spectrometric measurements over solid lithium oxide. From the measurements of the gaseous equilibria Li2O(g) + Li2(g)⇄Li3O(g) + Li(g), 2 Li2O(g)⇄Li3O(g) + LiO(g), Li 2O2(g) + Li2(g)⇄2 Li2O(g) and Li2O2(g) + Li2(g)⇄Li3O(g) + LiO(g), the atomization energies D0o(Li3O) = 229.0±10 kcal/mol and D0o(Li2O 2) = 293.0±12 kcal/mol were obtained. The ionization potentials were determined as I.P.(Li3O) = 4.54±0.2 eV and I.P.(Li2O2) = 7.88±0.2 eV, from which the binding energies D0o(Li3O+) = 438.0±15 kcal/mol and D0o(Li2O 2+) = 425.0±16 kcal/mol result. The heats of formation were determined as: ΔH°0(Li3O) = -(54.5±10) kcal/mol and ΔH°0(Li2O 2) = -(98.0±12) kcal/mol. © 1979 American Institute of Physics.