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Oxidation & Electrons | Appearance & Characteristics Reactions | Compounds | Radius | Conductivity Abundance & Isotopes 
Bromine in sample-tube. (Photo by Greenhorn1) |
General:
| Name: Bromine | Symbol: Br |
| Type: Halogen | Atomic weight: 79.904 |
| Density @ 293 K: 3.122 g/cm3 | Atomic volume: 23.5 cm3/mol |
| Discovered: Bromine was discovered by A.J. Balard in 1826 in Montpellier, France. The name comes from the Greek word "bromos" meaning "stench". | |
States
| State (s, l, g): liquid | |
| Melting point: 277 K (-7 oC) | Boiling point: 332 K (58.9 oC) |
Energies
| Specific heat capacity: 0.473 J g-1 K-1 | Heat of atomization: 112 kJ mol-1 |
| Heat of fusion: 10.57 kJ mol-1 of Br2 | Heat of vaporization: 29.96 kJ mol-1 of Br2 |
| 1st ionization energy: 1139.9 kJ mol-1 | 2nd ionization energy: 2103.4 kJ mol-1 |
| 3rd ionization energy: 3473.4 kJ mol-1 | Electron affinity: 324.7 kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,18,7 | Electron configuration: [Ar] 3d10 4s2 4p5 |
| Minimum oxidation number: -1 | Maximum oxidation number: 7 |
| Min. common oxidation no.: -1 | Max. common oxidation no.: 5 |
| Electronegativity (Pauling Scale): 2.96 | Polarizability volume: 3.1 Å3 |
Appearance & Characteristics
| Structure: layers of Br2 | Color: red-brown |
| Hardness: mohs | |
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Harmful effects:
Bromine is poisonous and causes skin burns. Characteristics: Pure bromine is diatomic, Br2. Bromine is the only nonmetallic element that is liquid at ordinary temperatures. It is a dense, reddish-brown liquid which evaporates easily at room temperature to a red vapor with a strong, chlorine-like odor. Bromine is less reactive than chlorine or fluorine but more reactive than iodine. It forms compounds with many elements and, like chlorine, acts as a bleaching agent. Uses: Bromine compounds are used as pesticides, dyestuffs, water purification compounds, and as a flame-retardants in plastics. 1,2-dibromoethane is used as an anti-knock agent to raise the octane number of gasoline and allow engines to run more smoothly. This application has declined as a result of environmental legislation. Potassium bromide is used as a source of bromide ions for the manufacture of silver bromide for photographic film. |
Reactions
| Reaction with air: none | Reaction with 6 M HCl: none, dissolves Br2(aq) |
| Reaction with 15 M HNO3: | Reaction with 6 M NaOH: mild, ⇒ OBr-, Br- |
Compounds
| Oxide(s): Br2O, BrO2 | Chloride(s): BrCl |
| Hydride(s): HBr |
Radius
| Atomic radius: 115 pm | Ionic radius (1+ ion): pm |
| Ionic radius (2+ ion): pm | Ionic radius (3+ ion): pm |
| Ionic radius (2- ion): pm | Ionic radius (1- ion): 182 pm |
Conductivity
| Thermal conductivity: 0.12 W m-1 K-1 | Electrical conductivity: 1.0 x 10-10 S m-1 |
Abundance & Isotopes
| Abundance earth's crust: 2.4 parts per million, 0.6 by moles | |
| Abundance solar system: parts per billion by weight, parts per billion by moles | |
| Cost, pure: $5 per 100g | |
| Cost, bulk: $0.15 per 100g | |
| Source: Bromine is obtained from natural brine deposits. Some bromine is still extracted today from seawater, which contains only about 70 ppm. | |
| Isotopes: 26 whose half-lives are known, with mass numbers 68 to 94. Of these, only two are stable: 79Br and 81Br. | |
