It was three years ago that I first blogged on the topic of the Sn2 reaction. Matthias Bickelhaupt had suggested that the Sn2 reaction involving displacement at a carbon atom was an anomaly; the true behaviour was in fact exhibited by the next element down in the series, silicon.

Science is about making connections. And these can often be made between the most unlikely concepts. Thus in the posts I have made about pentavalent carbon , one can identify a series of conceptual connections.