In the hydride field, in particular, we were looking at the hydrides of boron, aluminium and gallium. The boron work had actually started in Nottingham with John Morris and John Wright, and they did some very nice work of adding borane, BH₃, to unsaturated organic compounds, which was not unlike the Herb Brown work on hydroboration. But we didn’t pursue that further when I went to Newcastle.

In Newcastle we went more on the chemistry of the higher boron hydrides, and particularly in later years on metalloboranes. That is an interesting field. If one thinks that boron is the element immediately before carbon in the periodic table, so it has the same number of orbitals, but one too few electrons, and that has developed into a concept of electron-deficient compounds, but as Riley Schaeffer once said, ‘There’s no such thing as an electron-deficient compound, only a theory-deficient chemist’, and we took that very much on board – there was the right number for the structures that were being involved.

Now, one had the view that, even so, there were fewer electrons available for bonding, and so the boranes appeared to be electron acceptors, that would be their natural thing. We developed a concept of boranes as ligands, and that was an entirely novel thing.