Neon

Neon is a noble gas: it forms no stable compounds and makes up about 18 parts per million of the air. It is collected as a byproduct when air is liquefied and separated to make oxygen and nitrogen. William Ramsay and Morris Travers discovered it in 1898, naming it from the Greek word for new.

When electricity passes through neon in a glass tube, it glows a bright red-orange, the classic neon sign. Other colors in such signs come from other gases or coated tubes. Neon is also the main gas in the excimer lasers used to pattern the tiniest features on computer chips, and liquid neon is a powerful refrigerant.