ELEMENTLE

Element 35 · Halogen

Bromine

Period 4 · Group 17

Bromine (from Ancient Greek:βρῶμος, brómos, meaning "stench") is a chemical element with symbol Br, and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826.

Three reasons Bromine stands out

  1. 1

    Used in flame retardants and hot tubs.

  2. 2

    It is one of only two elements that exist as a liquid at room temperature, the other being mercury.

  3. 3

    Light-sensitive silver bromide crystals are the key ingredient that makes traditional photographic film work.

The only liquid nonmetal

Bromine is a fuming red-brown liquid at room temperature, its molecules volatile enough to fill the space above it with corrosive vapor. Bromide compounds occur throughout seawater. Photography, flame retardants, drilling fluids, and medicines have all drawn on bromine chemistry, sometimes with environmental costs.

Bromine at a glance
Atomic number / protons35
SymbolBr
Family (Elementle)Halogen
Classification (PubChem)Halogen
Period4
Group17
Atomic mass (u)79.90
Standard stateLiquid
Electron configuration[Ar]4s2 3d10 4p5
Reported oxidation states+5, +1, -1
Electronegativity (Pauling)2.96
Atomic radius (pm)183
First ionization energy (eV)11.814
Electron affinity (eV)3.365
Density (g/cm³)3.11
Melting point265.95 K (-7.2 °C)
Boiling point331.95 K (58.8 °C)
Discovery (PubChem)1826

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: Bromine · Bromine 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.