The bonds that bind

Early in 1916, two scientists were independently converging on an important puzzle. Gilbert Lewis was a US chemist with wide-ranging interests who was something of a maverick. Walther Kossel was a German physicist from a more conventional academic background who focused on a narrower band of problems. They addressed two fundamental questions – what binds elements together to form compounds, and why are some eager to combine and others reluctant? Their answers differed, but were clearly pointing in the same direction.

A year later the US was at war with Germany. Kossel was already working to improve military radio equipment, and soon afterwards Lewis began training army personnel to cope with poison gas. Today the war has passed into history, but the theory that Kossel and Lewis pioneered remains central to chemistry.