Calculation of the electronic structure of boranes by the self-consistent molecular orbital method. Part I. B10H14 and some neutral chloroboranes

Abstract

The electronic structures of the boron chlorides, BCl₃, B₂Cl₄, and B₄Cl₄, together with the neutral borane B₁₀H₁₄, are examined by an improved version of the SCMO method including all valence electrons. We find that the results for BCl₃ show a marked polarisation of electrons towards chlorine and that the highest bonding orbital is degenerate and of σ type. For B₂Cl₄ the perpendicular isomer is more stable than the planar one and the B–B bond is overall not strong. The polarity is rather less marked than in BCl₃. For B₄Cl₄ the polarity across the B–Cl bond is quite weak and the molecule probably owes its stability to a build-up of charge inside the polyhedron.

For B₁₀H₁₄ our results concur substantially with previous work but the charge distribution shows that all boron atoms are formally negatively charged. This agrees generally with experimental data.