Bromine

Bromine, 35Br
Bromine
Pronunciation/ˈbroʊmiːn, -mɪn, -maɪn/ ​(BROH-meen, -⁠min, -⁠myne)
Appearancereddish-brown
Standard atomic weight Ar°(Br)
[79.901, 79.907]
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 
selenium ← bromine → krypton
Atomic number (Z)35
Groupgroup 17 (halogens)
Periodperiod 4
Block  p-block
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
Critical point588 K, 10.34 MPa
Heat of fusion(Br2) 10.571 kJ/mol
Heat of vaporization(Br2) 29.96 kJ/mol
Molar heat capacity(Br2) 75.69 J/(mol·K)
Vapor 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, 0, +1, +2, +3, +4, +5, +7 (a strongly acidic oxide)
ElectronegativityPauling scale: 2.96
Ionization 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 structure ​orthorhombic
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
Molar magnetic susceptibility−56.4×10−6 cm3/mol
CAS Number7726-95-6
History
Discovery and first isolationAntoine Jérôme Balard and Carl Jacob Löwig (1825)
Isotopes of bromine
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
79Br 51% stable
81Br 49% stable
 Category: Bromine
| references
A tube with bromine in it. At the bottom is bromine as a liquid and above it is bromine as a gas. The tube is sealed in an acrylic cube.

Bromine (Br) is a chemical element. Its atomic number (which is the number of protons in it) is 35, and its atomic weight is 80. It is part of the Group 17 elements (halogens) on the periodic table. It is diatomic, which means that two atoms are stuck together to make a molecule in any bromine sample.

Properties

Physical properties

Bromine is a red-brown liquid. Liquid elements are rare; only bromine and mercury are liquid at room temperature. It easily evaporates to make suffocating brown fumes. It has a bad smell. Its name means "stench of he-goats". It can become a metal at very high pressures.

It has two stable isotopes. They are 79Br and 81Br. There are about 29 other radioactive isotopes.

Chemical properties

Bromine is quite reactive. Its reactivity is between chlorine, which is more reactive, and iodine, which is less reactive. It reacts with metals and nonmetals. Phosphorus reacts violently with bromine. Aluminum reacts in a similar way. It can bleach things like chlorine. It reacts better in the light. It dissolves a little in water. Hot water makes it disproportionate into hydrobromic acid and hypobromous acid. Bromine can form compounds with substances such as sodium to form sodium bromide.

Chemical compounds

Bromine forms compounds in many oxidation states: –1, +1, +3, +5, and (sometimes) +7. –1 is the most common. It is found as bromide. Bromides are not reactive. They are colorless solids that dissolve in water easily. Covalent bromides can be liquids or gases. The other compounds are all strong oxidizing agents. Their chlorine cousins are more common. +1 has the hypobromites, which are unstable. +3 has the bromites. Bromine dioxide is the only common bromine compound found in the +4 oxidation state. +5 has the bromates, which are more common than all the other ones except the bromides. Bromates are strong oxidizing agents and are sometimes added to flour. +7 has the perbromates. Perbromates are very unstable.

Occurrence

Bromine is found as bromide in the ocean and in brine pools. The Dead Sea has a lot of bromide in it. Bromine is not an important part of our body, unlike its relatives chlorine and iodine.

Preparation

Bromine is made by bubbling chlorine gas through a solution of a bromide. The bromide is oxidized to bromine, while the chlorine is reduced to chloride.

Uses

It is mainly used to make organobromine compounds, organic compounds with bromine in them. Organobromines are used to put out fires. They used to be added to gasoline. Some were used as pesticides. Some inorganic bromides were used as sedatives. Bromine can also be used as a disinfectant. Silver bromide is used in film.

Safety

Bromine is toxic and corrosive to skin. Bromine gas is irritating when it is breathed in, too. Bromine can react violently with many things.

  1. ↑ "Standard Atomic Weights: Bromine". CIAAW. 2011.
  2. 1 2 Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.121. ISBN 1439855110.
  3. ↑ Br(II) is known to occur in bromine monoxide radical; see Kinetics of the bromine monoxide radical + bromine monoxide radical reaction
  4. ↑ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  5. ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  6. ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.