About

Bromine is a fuming reddish-brown liquid at room temperature, the only halogen element to exist in this state under standard conditions. It is highly reactive, corrosive, and has a strong, unpleasant odor. Bromine compounds are used widely as effective flame retardants, in water purification systems, and in the production of some pharmaceuticals and agricultural chemicals.

Atomic Properties

Atomic Number35

Atomic Weight79.904 u

Neutrons (common)45

Electron Configuration[Ar] 3d¹⁰ 4s² 4p⁵

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁵

Electrons per Shell2, 8, 18, 7

Electronegativity2.96

Electron Affinity324.6 kJ/mol

Oxidation States+7, +5, +3, +1, -1

Covalent Radius114 pm

Van der Waals Radius185 pm

Ionic Radius196 pm

Periodic Table Position

Group17

Period4

BlockP

Chemical SeriesHalogens

Physical Properties

State at STPliquid

Appearancefuming red-brown liquid

Crystal Structureorthorhombic

Magnetic Orderingdiamagnetic

Speed of Sound1,119 m/s

Thermal Properties

Melting Point265.8 K

Boiling Point332 K

Triple Point265.9 K

Thermal Conductivity0.122 W/(m·K)

Specific Heat0.474 J/(g·K)

Molar Heat75.7 J/(mol·K)

Heat of Fusion10.57 kJ/mol

Heat of Vaporization29.96 kJ/mol

Abundance

In Earth's Crust2.4 ppm

In Ocean67.3 ppm

In Solar System0.009 ppm

In Human Body3.7 ppm

In Universe0.007 ppm

Discovery

Discovered byAntoine Balard & Carl Jacob Löwig

Discovery Year1,826

Occurrenceprimordial

CAS Number7726-95-6

Electron Configuration

Energy

↿⇂

↿

Isotopes of Bromine

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁷⁷Br	76.921379	—	57.04 h	Positron Emission, Electron Capture
⁷⁹Br	78.918340	50.69%	Stable	Stable
⁸⁰Br	79.918530	—	4.4205 h	Internal Transition, Beta Minus Decay
⁸¹Br	80.916290	49.31%	Stable	Stable
⁸²Br	81.916804	—	35.282 h	Beta Minus Decay
⁸³Br	82.915180	—	2.374 h	Beta Minus Decay

Interactive Visualization

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

View 3D Model of Bromine