Portrait of Hennig Brand

Adapted from ⁠an image by Joseph Wright of Derby (public domain), via Wikimedia Commons.

1630–1710

Hennig Brand

Discovered phosphorus in 1669.

Element

15PPhosphorus
1669

In 1669 Hennig Brand, an alchemist in Hamburg, boiled down urine and heated what was left until a vapour came off that glowed in the dark. Hoping it was the philosopher's stone, he kept the method secret.

Explore phosphorus

Brand boiled down urine and got a substance that glowed in the dark: white phosphorus. See its three forms.

One element, three forms

Same atoms, three different materials

White, red and black phosphorus are all pure phosphorus. The only difference is how the atoms are joined up, and that changes everything: one glows in the dark and bursts into flame on a warm day, one sits safely on a matchbox, and one is as calm as graphite.

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White phosphorus

Built from
Separate P₄ molecules: four atoms in a pyramid
Bond angle
60°, squeezed far tighter than phosphorus likes
Looks like
A soft, waxy, pale yellow solid
In air
Glows green in the dark; catches fire at about 30 °C
Made by
Condensing phosphorus vapour
Toxic?
Very. It’s stored under water
Density
1.82 g/cm³

Each P₄ pyramid has its bonds squeezed to 60°, like bent springs. They snap open easily, which makes white phosphorus fiercely reactive.

Warm them up

WhiteRedBlack
White phosphorus
Glows faintly (try lights off)
Red phosphorus
Nothing happens
Black phosphorus
Nothing happens

Phosphorus in history and today

  • Found in urine

    In 1669 Hennig Brand boiled down buckets of urine hoping to make gold. He got a waxy solid that glowed in the dark: white phosphorus. Its name is Greek for “light-bearer”.

  • Matches

    The first matches used white phosphorus, which poisoned the factory workers who made them. Safety matches keep red phosphorus on the side of the box instead: the strike turns a tiny amount into something that lights.

  • One atom thick

    Peel black phosphorus down to a single crinkled sheet and you get phosphorene, first made in 2014. Like graphene, it’s being studied for tiny, fast electronics.

Atoms are drawn smaller than their true size so the structures are clear, and use the standard model colour for phosphorus, orange. Red phosphorus is really a tangle of chains; one tidy chain is shown. Never try this at home: white phosphorus is dangerous.

Keep exploring

Where the dates and stories on this page come from; each event on the timeline links to its own source.