In this review, we focus on the aromaticity of a particular family of organometallic compounds known as metallabenzenes, which are characterized by the formal replacement of a CH group in benzene by an isolobal transition metal fragment.

In this perspective, different expert opinions are gathered on the definition and concept of aromaticity.

Herein we propose a general mechanism for the racemization of [n]helicenes up to n = 24. It is a concerted process for n = 4–7, but a multi-step mechanism is followed for n ≥ 8, involving 2n − 14 intermediates. The changes in the barriers are a delicate consequence of the steric hindrance and the π-interactions.

A quasi-planar member of the so-called ‘Wankel motor’ family, B₁₈²⁻, is found.

Would it be possible to eventually derive a simple methodology to predict the structure adopted by boron clusters based on its structural transformation induced by the doping with one or two metal atoms?