ELEMENTLE

Element 15 · Nonmetal

Phosphorus

Period 3 · Group 15

Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but due to its high reactivity, phosphorus is never found as a free element on Earth. Instead phosphorus-containing minerals are almost always present in their maximally oxidised state, as inorganic phosphate rocks.

Three reasons Phosphorus stands out

  1. 1

    Essential for life, found in DNA.

  2. 2

    Its white form glows in the dark, which is how it got its name meaning "light bearer" in Greek.

  3. 3

    It was first discovered in 1669 by an alchemist who extracted it from evaporated human urine.

Life’s energetic middleman

Phosphorus atoms sit in DNA’s backbone and in ATP, the molecule cells use to move energy around. White phosphorus glows faintly as it reacts with air and can ignite spontaneously, whereas red phosphorus is far safer. Agriculture depends on phosphate fertilizers, but excess runoff can overwhelm waterways.

Phosphorus at a glance
Atomic number / protons15
SymbolP
Family (Elementle)Nonmetal
Classification (PubChem)Nonmetal
Period3
Group15
Atomic mass (u)30.97376200
Standard stateSolid
Electron configuration[Ne]3s2 3p3
Reported oxidation states+5, +3, -3
Electronegativity (Pauling)2.19
Atomic radius (pm)180
First ionization energy (eV)10.487
Electron affinity (eV)0.746
Density (g/cm³)1.82
Melting point317.3 K (44.15 °C)
Boiling point553.65 K (280.5 °C)
Discovery (PubChem)1669

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Phosphorus · Phosphorus on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.