Pictures of the molecular world

The conventions used to represent chemical structures are so deeply ingrained in the understanding and teaching of chemistry that they form a language every chemist learns to communicate in. However, representation of the structures of chemical compounds is also at the heart of many misconceptions that arise in chemistry teaching and is one reason that it is perceived as a ‘difficult’ subject.

Ever since chemists began to realise that atoms in molecules could be arranged in multiple ways to make different chemical compounds, they have been developing ways to represent these arrangements.

The representation of chemical structures, like any language, was built up from a gradual understanding of the world it describes, with new conventions being added and inaccurate or unwieldy representations falling out of use.

From line bound structures to sausages, circles and 3D, our representation of chemical structures has gone through may changes since the mid-19th century when chemists began to consider how the ratios of elements in compounds were arranged at the molecular level. Matthew Lickiss follows this journey of discovery anddocuments the changing faces of the molecular world.