About

Phosphorus is a highly reactive nonmetal that exists in several allotropic forms (white, red, black). It is essential for life, forming the phosphate backbone of DNA and RNA and being a key part of ATP, the energy currency of cells. It's widely used in agricultural fertilizers to promote plant growth, as well as in detergents, and, historically, in strike-anywhere matches.

Atomic Properties

Atomic Number15

Atomic Weight30.974 u

Neutrons (common)16

Electron Configuration[Ne] 3s² 3p³

Full Configuration1s² 2s² 2p⁶ 3s² 3p³

Electrons per Shell2, 8, 5

Electronegativity2.19

Electron Affinity72 kJ/mol

Oxidation States+5, +3, -3

Covalent Radius109 pm

Van der Waals Radius180 pm

Ionic Radius212 pm

Periodic Table Position

Group15

Period3

BlockP

Chemical SeriesOther nonmetals

Physical Properties

State at STPsolid

AppearanceExists in three main allotropes: waxy white, red, and black solid

Crystal Structureorthorhombic

Magnetic Orderingdiamagnetic

Thermal Properties

Melting Point317.3 K

Boiling Point553.65 K

Triple Point317.3 K

Thermal Expansion0 1/K

Thermal Conductivity0.236 W/(m·K)

Specific Heat0.769 J/(g·K)

Molar Heat23.824 J/(mol·K)

Heat of Fusion0.66 kJ/mol

Heat of Vaporization12.4 kJ/mol

Abundance

In Earth's Crust1,050 ppm

In Ocean0.06 ppm

In Solar System7.78 ppm

In Human Body11,000 ppm

In Universe7 ppm

Discovery

Discovered byHennig Brand

Discovery Year1,669

Occurrenceprimordial

CAS Number7723-14-0

Electron Configuration

Energy

↿⇂

↿

Isotopes of Phosphorus

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
³¹P	30.973762	100%	Stable	Stable
³²P	31.973907	—	14.269 d	Beta Minus Decay
³³P	32.971725	—	25.35 d	Beta Minus Decay

Interactive Visualization

Explore the 3D Bohr model of Phosphorus in our interactive viewer.

View 3D Model of Phosphorus