Abstract:

Gaseous H-BF2 and D-BF2 were obtained by a new method of preparation. Analysis of high-resolution ir spectra gave approximate values for the B-F distance (1.30±0.15 Å) and the F-B-F angle (120°±5°). Five of the six fundamentals were observed and assigned unambiguously: v2=2620 and 1962 cm-1, B-H and B-D stretches; v1 =1166 and 1128 cm-1, 11B-F symmetric stretches in H-BF2 and D-BF2; v3 = 545 and 540 cm-1, F-11B-F bending in H-BF2 and D-BF2; and v4=1402, 1392, 1419 cm-1, 11B-F asymmetric stretches in H-BF2 and D- 11BF2 and 10B-F stretch in D- 10BF2, respectively; v6=944, 924, 810, 790 cm-1, out-of-plane deformation in H-10BF2, H-11BF2, D-10BF2, and D- 11BF2, respectively. The H-B-F bendmg appears to have a frequency v5 = 1200 cm-1 for H-11BF2 and is estimated at 887 cm-1 for D-11BF2. A force-constant calculation was made, obtaining the following values (in millidynes per angstrom) fD = 3.66, fd= 6.625, f d′ = 0.725, fDd = 0.37, fr = 0.772.