Bromine

  • bromine, 35br
    bromine 25ml (transparent).png
    bromine
    pronunciationn/ (broh-meen, -⁠min, -⁠myn)
    appearancereddish-brown
    standard atomic weight ar, std(br)[79.90179.907] conventional: 79.904
    bromine in the periodic table
    hydrogen helium
    lithium beryllium boron carbon nitrogen oxygen fluorine neon
    sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
    potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
    rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
    caesium barium lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury (element) thallium lead bismuth polonium astatine radon
    francium radium actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson
    cl

    br

     i 
    seleniumbrominekrypton
    atomic number (z)35
    groupgroup 17 (halogens)
    periodperiod 4
    blockp-block
    element category  reactive nonmetal
    electron configuration[ar] 3d10 4s2 4p5
    electrons per shell2, 8, 18, 7
    physical properties
    phase at stpliquid
    melting point(br2) 265.8 k ​(−7.2 °c, ​19 °f)
    boiling point(br2) 332.0 k ​(58.8 °c, ​137.8 °f)
    density (near r.t.)br2, liquid: 3.1028 g/cm3
    triple point265.90 k, ​5.8 kpa[1]
    critical point588 k, 10.34 mpa[1]
    heat of fusion(br2) 10.571 kj/mol
    heat of vaporisation(br2) 29.96 kj/mol
    molar heat capacity(br2) 75.69 j/(mol·k)
    vapour pressure
    p (pa) 1 10 100 1 k 10 k 100 k
    at t (k) 185 201 220 244 276 332
    atomic properties
    oxidation states−1, +1, +3, +4, +5, +7 (a strongly acidic oxide)
    electronegativitypauling scale: 2.96
    ionisation energies
    • 1st: 1139.9 kj/mol
    • 2nd: 2103 kj/mol
    • 3rd: 3470 kj/mol
    atomic radiusempirical: 120 pm
    covalent radius120±3 pm
    van der waals radius185 pm
    color lines in a spectral range
    spectral lines of bromine
    other properties
    natural occurrenceprimordial
    crystal structureorthorhombic
    orthorhombic crystal structure for bromine
    speed of sound206 m/s (at 20 °c)
    thermal conductivity0.122 w/(m·k)
    electrical resistivity7.8×1010 Ω·m (at 20 °c)
    magnetic orderingdiamagnetic[2]
    magnetic susceptibility−56.4·10−6 cm3/mol[3]
    cas number7726-95-6
    history
    discovery and first isolationantoine jérôme balard and carl jacob löwig (1825)
    main isotopes of bromine
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    79br 51% stable
    81br 49% stable
    category category: bromine
    | references
    bromine 3d molecule, br2

    bromine is a chemical element with symbol br and atomic number 35. it is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured gas. its properties are thus intermediate between those of chlorine and iodine. isolated independently by two chemists, carl jacob löwig (in 1825) and antoine jérôme balard (in 1826), its name was derived from the ancient greek βρῶμος ("stench"), referencing its sharp and disagreeable smell.

    elemental bromine is very reactive and thus does not occur free in nature, but in colourless soluble crystalline mineral halide salts, analogous to table salt. while it is rather rare in the earth's crust, the high solubility of the bromide ion (br) has caused its accumulation in the oceans. commercially the element is easily extracted from brine pools, mostly in the united states, israel and china. the mass of bromine in the oceans is about one three-hundredth that of chlorine.

    at high temperatures, organobromine compounds readily dissociate to yield free bromine atoms, a process that stops free radical chemical chain reactions. this effect makes organobromine compounds useful as fire retardants, and more than half the bromine produced worldwide each year is put to this purpose. the same property causes ultraviolet sunlight to dissociate volatile organobromine compounds in the atmosphere to yield free bromine atoms, causing ozone depletion. as a result, many organobromide compounds—such as the pesticide methyl bromide—are no longer used. bromine compounds are still used in well drilling fluids, in photographic film, and as an intermediate in the manufacture of organic chemicals.

    large amounts of bromide salts are toxic from the action of soluble bromide ion, causing bromism. however, a clear biological role for bromide ion and hypobromous acid has recently been elucidated, and it now appears that bromine is an essential trace element in humans. the role of biological organobromine compounds in sea life such as algae has been known for much longer. as a pharmaceutical, the simple bromide ion (br) has inhibitory effects on the central nervous system, and bromide salts were once a major medical sedative, before replacement by shorter-acting drugs. they retain niche uses as antiepileptics.

  • history
  • properties
  • chemistry and compounds
  • occurrence and production
  • applications
  • biological role and toxicity
  • references
  • bibliography
  • external links

Bromine, 35Br
Bromine 25ml (transparent).png
Bromine
Pronunciationn/ (BROH-meen, -⁠min, -⁠myn)
Appearancereddish-brown
Standard atomic weight Ar, std(Br)[79.90179.907] conventional: 79.904
Bromine in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Cl

Br

 I 
seleniumbrominekrypton
Atomic number (Z)35
Groupgroup 17 (halogens)
Periodperiod 4
Blockp-block
Element category  Reactive nonmetal
Electron configuration[Ar] 3d10 4s2 4p5
Electrons per shell2, 8, 18, 7
Physical properties
Phase at STPliquid
Melting point(Br2) 265.8 K ​(−7.2 °C, ​19 °F)
Boiling point(Br2) 332.0 K ​(58.8 °C, ​137.8 °F)
Density (near r.t.)Br2, liquid: 3.1028 g/cm3
Triple point265.90 K, ​5.8 kPa[1]
Critical point588 K, 10.34 MPa[1]
Heat of fusion(Br2) 10.571 kJ/mol
Heat of vaporisation(Br2) 29.96 kJ/mol
Molar heat capacity(Br2) 75.69 J/(mol·K)
Vapour pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 185 201 220 244 276 332
Atomic properties
Oxidation states−1, +1, +3, +4, +5, +7 (a strongly acidic oxide)
ElectronegativityPauling scale: 2.96
Ionisation energies
  • 1st: 1139.9 kJ/mol
  • 2nd: 2103 kJ/mol
  • 3rd: 3470 kJ/mol
Atomic radiusempirical: 120 pm
Covalent radius120±3 pm
Van der Waals radius185 pm
Color lines in a spectral range
Spectral lines of bromine
Other properties
Natural occurrenceprimordial
Crystal structureorthorhombic
Orthorhombic crystal structure for bromine
Speed of sound206 m/s (at 20 °C)
Thermal conductivity0.122 W/(m·K)
Electrical resistivity7.8×1010 Ω·m (at 20 °C)
Magnetic orderingdiamagnetic[2]
Magnetic susceptibility−56.4·10−6 cm3/mol[3]
CAS Number7726-95-6
History
Discovery and first isolationAntoine Jérôme Balard and Carl Jacob Löwig (1825)
Main isotopes of bromine
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
79Br 51% stable
81Br 49% stable
Category Category: Bromine
| references
Bromine 3D molecule, Br2

Bromine is a chemical element with symbol Br and atomic number 35. It is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured gas. Its properties are thus intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived from the Ancient Greek βρῶμος ("stench"), referencing its sharp and disagreeable smell.

Elemental bromine is very reactive and thus does not occur free in nature, but in colourless soluble crystalline mineral halide salts, analogous to table salt. While it is rather rare in the Earth's crust, the high solubility of the bromide ion (Br) has caused its accumulation in the oceans. Commercially the element is easily extracted from brine pools, mostly in the United States, Israel and China. The mass of bromine in the oceans is about one three-hundredth that of chlorine.

At high temperatures, organobromine compounds readily dissociate to yield free bromine atoms, a process that stops free radical chemical chain reactions. This effect makes organobromine compounds useful as fire retardants, and more than half the bromine produced worldwide each year is put to this purpose. The same property causes ultraviolet sunlight to dissociate volatile organobromine compounds in the atmosphere to yield free bromine atoms, causing ozone depletion. As a result, many organobromide compounds—such as the pesticide methyl bromide—are no longer used. Bromine compounds are still used in well drilling fluids, in photographic film, and as an intermediate in the manufacture of organic chemicals.

Large amounts of bromide salts are toxic from the action of soluble bromide ion, causing bromism. However, a clear biological role for bromide ion and hypobromous acid has recently been elucidated, and it now appears that bromine is an essential trace element in humans. The role of biological organobromine compounds in sea life such as algae has been known for much longer. As a pharmaceutical, the simple bromide ion (Br) has inhibitory effects on the central nervous system, and bromide salts were once a major medical sedative, before replacement by shorter-acting drugs. They retain niche uses as antiepileptics.