Carole A. Morrison, Bruce A. Smart, Paul T. Brain, Colin R. Pulham, David W. H. Rankin and Anthony J. Downs
Structural trends in the family of compounds H2MB3H8 (M = B, Al, Ga or In) have been investigated by ab initio molecular orbital calculations. In addition, the molecular structure of the arachno borane H2GaB3H8 has been re-determined by gas-phase electron diffraction using the SARACEN method of structural analysis. Salient structural parameters (rα0) were found to be: r[B(1)![[hair space]](https://www.rsc.org/images/entities/char_200a.gif)
· · ·![[hair space]](https://www.rsc.org/images/entities/char_200a.gif)
Ga(2)] 231.0(2), r[B(1)–B(3)] 177.9(13), r[B(1)–B(4)] 184.0(13), r[B(1)–H(1,2)] 123.0(11), r[Ga(2)–H(1,2)] 181(4), r[B(1)–H(1,4)] 123.7(11), r[B(4)–H(1,4)] 142.2(18) pm; butterfly angle 117.1(7)°.