Phosphorus (P)

Other nonmetals · Period 3 · Solid

Explore phosphorus isotopes Locate in periodic table

Element identity

Atomic number (Z): 15
Symbol: P
Atomic weight / isotope mass number: 30.973 761 998(5)
Category: Other nonmetals
Physical state (reference): Solid
Period: 3
Group (reference): 15
Block: p

Physical properties

Appearance: Colourless, waxy white, yellow, scarlet, red, violet, black
Density: Black: 2.69 g·cm⁻³ Red: ≈ 2.2–2.34 g·cm⁻³ Violet: 2.36 g·cm⁻³ White: 1.823 g·cm⁻³
Melting point: White: 44.2 °C Black: 610 °C
Boiling point: White: 280.5 °C
Sublimation point: Red: ≈ 416–590 °C Violet: 620 °C

Atomic and material properties

Electron configuration: [Ne] 3s² 3p³
Electrons per shell: K2 L8 M5
Oxidation states: 5, 4, 3, 2, 1, −1, −2, −3
Electronegativity (Pauling): 2.19
Atomic radius: 98 pm
Covalent radius: 107±3 pm
Molar ionization energies: 1st: 1011.8 kJ·mol⁻¹ 2nd: 1907 kJ·mol⁻¹ 3rd: 2914.1 kJ·mol⁻¹ 4th: 4963.6 kJ·mol⁻¹ 5th: 6273.9 kJ·mol⁻¹ 6th: 21,267 kJ·mol⁻¹ 7th: 25,431 kJ·mol⁻¹ 8th: 29,872 kJ·mol⁻¹ 9th: 35,905 kJ·mol⁻¹ 10th: 40,950 kJ·mol⁻¹ 11th: 46,261 kJ·mol⁻¹ 12th: 54,110 kJ·mol⁻¹ 13th: 59,024 kJ·mol⁻¹ 14th: 271,791 kJ·mol⁻¹ 15th: 296,195 kJ·mol⁻¹
Thermal conductivity: White: 0.236 W·m⁻¹·K⁻¹ Black: 12.1 W·m⁻¹·K⁻¹
Molar heat capacity: White: 23.824 J·mol⁻¹·K⁻¹
Crystal structure: Body-centered cubic
CAS number: White: 12185-10-3 Red: 7723-14-0

Property source: Wikipedia — Phosphorus, adapted from the Nuclides App snapshot. Quoted conditions and qualifiers are retained.

Sources and interpretation

Snapshot exported 24 October 2026 from the element assets used by Nuclides. Properties are a reference compilation, not a new evaluation. Missing values are shown as “Not available”. Density and phase depend on temperature, pressure and allotrope; retained conditions are part of the quoted property.

Atomic weight is dimensionless. Parentheses give uncertainty in the last quoted digits. A single integer in square brackets is an isotope mass number, not a standard atomic weight. The snapshot can differ from current evaluations; consult CIAAW standard atomic weights and the IUPAC periodic table for current values and conventions.

Element properties in the App snapshot are adapted from Wikipedia. Each element page links to its source article; text adaptations are available under CC BY-SA 4.0. No third-party images are included.

Go from elements to nuclear data

Keep Nuclides on your phone.

Explore connected element and nuclide references, decay chains and calculators in the app. See each store for pricing and in-app purchases.