Thermochemical properties of gaseous Li2and Li3

摘要

Using the Knudsen effusion mass spectrometric technique, the gas species Li(g), Li2(g), and Li3(g) have been observed over liquid lithium. The atomization energies of Li2(g) and Li3(g):D0deg; (Li2) =25.5plusmn;1.5 kcal/mole andD0deg; (Li3) =41.5plusmn;4.0 kcal/mole, were derived from the study of the various gaseous equilibria: Li(s,l) rarr;Li(g) (1), 2Li(s,l) rarr;Li2(g) (2), Li2(g) rarr;2Li(g) (3), 3Li(s,l) rarr;Li3(g) (4), 2Li2(g) rarr;Li3(g)+Li(g) (5). The following heats of formation were also obtained: Dgr;H0deg; (Li) =38.5plusmn;1.0 kcal/mole, Dgr;H0deg; (Li2) =51.5plusmn;2.0 kcal/mole, Dgr;H0deg; (Li3) =73.0plusmn;4.0 kcal/mole. The ionization potentials of Li2and Li3were determined as 4.86plusmn;0.1 and 4.35plusmn;0.2 eV, respectively, from which the binding energiesD0deg; (Li+2) =37.7plusmn;2.0 andD0deg; (Li+3) =65.5plusmn;4.3 kcal/mole result.