Abstract:
Thermodynamic properties for the negative ions of boron and aluminium fluorides were obtained by means of the effusion-mass spectrometric method over the temperature range 1100 to 1900 K. Studies were conducted involving negative ions with neutral molecules for the isomolecular reactions BF–2(g)+ F(g)→BF2(g)+ F–(g), BF3(g)+ BF–2(g)→BF(g)+ BF–4(g), AlF2(g)+ F–(g)→AlF–2(g)+ F(g) and 2AlF2(g)+ AlF–2(g)→2AlF(g)+ AlF–4(g). The heats of formation, ΔHf298, for the ions BF–2(g), AlF–2(g), AlF–4(g), and BF–4(g) obtained from the reaction thermodynamics were – 191.7 ± 3, – 232.1 ± 3, – 500 ± 3 and [gt-or-equal]– 433 kcal mol–1, respectively. The electron affinities for BF2 and AlF2 were 50.7 ± 3 and 53.1 ± 3 kcal mol–1, respectively.
