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Bromine Facts

Bromine Chemical & Physical Properties


Bromine is a heavy, reddish-brown liquid.

Bromine is a heavy, reddish-brown liquid. It is the only non-metallic element that is liquid at room temperature.

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This is the electron configuration of a bromine atom.

This is the electron configuration of a bromine atom.

This is bromine on the periodic table.

This is bromine on the periodic table.

Todd Helmenstine

Atomic Number: 35

Symbol: Br

Atomic Weight: 79.904

Electron Configuration: [Ar]4s23d104p5

Word Origin: Greek bromos: stench

Element Classification: Halogen

Discovery: Antoine J. Balard (1826, France)

Density (g/cc): 3.12

Melting Point (°K): 265.9

Boiling Point (°K): 331.9

Appearance: reddish-brown liquid, metallic luster in solid form

Isotopes: There are 29 known isotopes of bromine ranging from Br-69 to Br-97. There are 2 stable isotopes: Br-79 (50.69% abundance) and Br-81 (49.31% abundance).

Atomic Volume (cc/mol): 23.5

Covalent Radius (pm): 114

Ionic Radius: 47 (+5e) 196 (-1e)

Specific Heat (@20°C J/g mol): 0.473 (Br-Br)

Fusion Heat (kJ/mol): 10.57 (Br-Br)

Evaporation Heat (kJ/mol): 29.56 (Br-Br)

Pauling Negativity Number: 2.96

First Ionizing Energy (kJ/mol): 1142.0

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

Lattice Structure: Orthorhombic

Lattice Constant (Å): 6.670

Magnetic Ordering: nonmagnetic

Electrical Resistivity (20 °C): 7.8×1010  Ω·m

Thermal Conductivity (300 K): 0.122  W·m−1·K−1

CAS Registry Number: 7726-95-6

Bromine Trivia:

  • Bromine is named after the Greek word bromos meaning stench because bromine smells...'stinky'.
  • Bromine was nearly discovered by two other chemists before Antoine Jerome Balard published his discovery. The first was in 1825 by the German chemist Justus von Liebig. He was sent a sample of salt water to analyze from a nearby town. He thought the brown liquid he separated from the salt water was a simple mixture of iodine and chlorine. After he learned of Balard's discovery, he went back and checked. His liquid was the newly discovered bromine. The other discoverer was a chemistry student named Carl Loewig. He separated the same brown liquid in 1825 from another sample of salt water. His professor asked him to prepare more of the brown liquid for further testing and soon learned of Balard's bromine.
  • Elemental bromine is a toxic substance and can cause corrosion burns when exposed to skin.
  • Compounds containing bromine in the -1 oxidation state are called bromides.
  • Bromine is the tenth most abundant element in sea water with an abundance of 67.3 mg/L.
  • Bromine is the 64th most abundant element in the Earth's crust with an abundance of 2.4 mg/kg.
  • At room temperature, elemental bromine is a reddish-brown liquid. The only other element that is a liquid at room temperature is mercury.
  • Bromine is used in many fire retardant compounds.
  • Bromide compounds used to be used as sedatives.
  • The ancient royal purple dye called Tyrian Purple is a bromine compound.
  • Bromine was used in leaded fuels to help prevent engine knock.
  • Herbert Dow, founder of the Dow Chemical Company started his business separating bromine from brine waters of the Midwestern United States.
Quiz: Test your new bromine knowledge with the Bromine Facts Quiz

Sources: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952) International Atomic Energy Agency ENSDF database (Oct 2010)

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