In the previous post, I referred to a recently published review on hypervalency[cite]10.1039/C5SC02076J[/cite] which introduced a very simple way (the valence electron equivalent γ) of quantifying the effect. Diazomethane was cited as one example of a small molecule exhibiting hypervalency (on nitrogen) by this measure.

One thread that runs through this blog is that of hypervalency. It was therefore nice to come across a recent review of the concept[cite]10.1039/c5sc02076j[/cite] which revisits the topic, and where a helpful summary is given of the evolving meanings over time of the term hypervalent.