Letters: February 2018

It is very true that today ‘visualising molecules as 3D objects (as anticipated by van’t Hoff and Lebel over one hundred years ago) is secondary school chemistry’ (Chemistry World, September 2017, p32). In particular, van’t Hoff, spoke of ‘the place atoms occupied in space’, creating the impression that the molecules formed by the corresponding atoms is a fixed structure regardless of the space it occupies. However, to what state did van’t Hoff refer? The crystalline solid, the liquid, the solution, the vapour or the gas? This has important consequences in the field of stereochemistry.