Phosphorus

Phosphorus is a reactive nonmetal that comes in several forms: white phosphorus glows faintly and catches fire in air, while red phosphorus is stable and is used on matchbox strikers. Hennig Brand discovered it in 1669 by boiling down urine. It is mined as phosphate rock, and most ends up in fertilizer, since every living cell needs it.

In the television, a trace of phosphorus cleans oxygen out of the melt when making springy phosphor bronze for connector contacts. In chips, phosphorus atoms implanted into doped silicon each bring one extra electron, creating the n-type regions of every transistor. Despite the name, the YAG phosphor in white LEDs contains no phosphorus.