Phosphorus: The Glow-in-the-Dark Element That Feeds the World

What exactly is phosphorus?

Phosphorus has the symbol P and atomic number 15 ². It is listed as a nonmetal that is solid at room temperature ². Its atomic mass is 30.97376200 ². It melts at 44.2 °C and boils at 280.5 °C, with a density of 1.82 g per cubic centimetre ².

All pure forms of phosphorus are highly reactive and are therefore never found in nature ¹. People can make pure phosphorus in the laboratory. The two most common forms are white phosphorus and red phosphorus ¹. These forms are called allotropes, which means the same element arranged in different ways. Phosphorus has only one stable isotope, 31P, and makes up about 0.1 percent of Earth's crust, generally as phosphate rock ¹.

Where is it found and what do we use it for?

Phosphorus is essential to all known forms of life ¹. In living things it often appears in organophosphates, which are carbon-based compounds that contain phosphate as a working part ¹. These include DNA, RNA, ATP, and phospholipids, complex compounds that help all cells function ¹. DNA and RNA carry genetic instructions. ATP stores and moves energy in cells. Phospholipids help form cell walls. The main mineral in bones and teeth is a modified form of hydroxyapatite, itself a phosphorus mineral ¹.

Most industrial production focuses on mining phosphate rock and changing it into phosphoric acid for phosphate-based fertilisers ¹. Phosphorus is an essential nutrient for plants, and often limits growth ¹. The natural phosphorus cycle is too slow to renew soil under intensive farming, so these fertilisers are vital to modern agriculture ¹. In 2024 the leading producers of phosphate ore were China, Morocco, the United States and Russia, with about two-thirds of estimated usable reserves in Morocco alone ¹. Other uses of phosphorus compounds include pesticides, food additives and detergents ¹. Red phosphorus is less dangerous than white phosphorus and is used in matches and fire retardants ¹.

What is surprising about phosphorus?

Phosphorus was the first element discovered in modern times, rather than known since ancient times ¹. The credit goes to Hamburg alchemist Hennig Brand in 1669 ¹. He was trying to make the fabled philosopher's stone and worked with urine, which contains dissolved phosphates from normal body processes ¹. By boiling it down and heating it strongly, he obtained a white, waxy substance that glowed in the dark and burned brightly ¹.

The name comes from the Greek word for light-bearer, a reference to Phosphorus, god of the morning star, inspired by the faint glow of white phosphorus in oxygen ¹. That glow also gave us the word phosphorescence, meaning glow after light, although scientists note that white phosphorus itself shows chemiluminescence from oxidation, not true phosphorescence ¹. White phosphorus is highly toxic and can catch fire easily, and its flammability has been weaponised in incendiaries ¹. Early matches used white phosphorus and were very dangerous, while later safety matches moved away from it ¹. For a time, bone ash was the main industrial source, until the 1840s, when phosphate rock and other methods became more important ¹.