   #copyright

Bromine

2007 Schools Wikipedia Selection. Related subjects: Chemical elements


                35              selenium ← bromine → krypton
                Cl
                ↑
                Br
                ↓
                I

                                  Periodic Table - Extended Periodic Table

                                                                   General
                                      Name, Symbol, Number bromine, Br, 35
                                                  Chemical series halogens
                                             Group, Period, Block 17, 4, p
                                          Appearance gas/liquid: red-brown
                                                    solid: metallic luster
                                              Atomic mass 79.904 (1) g/mol
                               Electron configuration [Ar] 3d^10 4s^2 4p^5
                                           Electrons per shell 2, 8, 18, 7
                                                       Physical properties
                                                              Phase liquid
                            Density (near r.t.) (liquid) 3.1028 g·cm^−3
                                                    Melting point 265.8  K
                                                      (-7.3 ° C, 19 ° F)
                                                     Boiling point 332.0 K
                                                   (58.8 ° C, 137.8 ° F)
                                           Critical point 588 K, 10.34 MPa
                                 Heat of fusion (Br[2]) 10.57 kJ·mol^−1
                           Heat of vaporization (Br[2]) 29.96 kJ·mol^−1
                                            Heat capacity (25 °C) (Br[2])
                                                 75.69 J·mol^−1·K^−1

   CAPTION: Vapor pressure

                                          P/Pa   1  10  100 1 k 10 k 100 k
                                         at T/K 185 201 220 244 276   332

                                                         Atomic properties
                                            Crystal structure orthorhombic
                                                   Oxidation states ±1, 5
                                                   (strongly acidic oxide)
                                    Electronegativity 2.96 (Pauling scale)
                                                       Ionization energies
                                          ( more) 1st: 1139.9 kJ·mol^−1
                                                    2nd: 2103 kJ·mol^−1
                                                    3rd: 3470 kJ·mol^−1
                                                      Atomic radius 115 pm
                                               Atomic radius (calc.) 94 pm
                                                    Covalent radius 114 pm
                                               Van der Waals radius 185 pm
                                                             Miscellaneous
                                             Magnetic ordering nonmagnetic
                          Electrical resistivity (20 °C) 7.8×10^10 Ω·m
                      Thermal conductivity (300 K) 0.122 W·m^−1·K^−1
                                         Speed of sound (20 °C) ? 206 m/s
                                             CAS registry number 7726-95-6
                                                         Selected isotopes

                 CAPTION: Main article: Isotopes of bromine

                                 iso    NA   half-life DM DE ( MeV)  DP
                                ^79Br 50.69% Br is stable with 44 neutrons
                                ^81Br 49.31% Br is stable with 46 neutrons

                                                                References

   Bromine ( IPA: /ˈbrəʊmiːn/, Greek: βρωμος, brómos, meaning "stench"),
   is a chemical element in the periodic table that has the symbol Br and
   atomic number 35. A halogen element, bromine is a red volatile liquid
   at standard room temperature which has a reactivity between chlorine
   and iodine. This element is corrosive to human tissue in a liquid state
   and its vapors irritate eyes and throat. Bromine vapors are very toxic
   upon inhalation.

Notable characteristics

   Bromine is the only liquid nonmetallic element at room temperature and
   one of five elements on the period table that are liquid at or close to
   room temperature. The pure chemical element has the physical form of a
   diatomic molecule, Br[2]. It is a heavy, mobile, reddish-brown liquid,
   that evaporates easily at standard temperature and pressures in a red
   vapor (its colour resembles nitrogen dioxide) that has a strong
   disagreeable odour resembling that of chlorine. A halogen, bromine
   resembles chlorine chemically but is less active. It is more active
   than iodine, however. Bromine is slightly soluble in water, and highly
   soluble in carbon disulfide, aliphatic alcohols (such as methanol), and
   acetic acid. It bonds easily with many elements and has a strong
   bleaching action.

   Bromine is highly reactive and is a powerful oxidizing agent in the
   presence of water. It reacts vigorously with amines, alkenes and
   phenols as well as aliphatic and aromatic hydrocarbons, ketones and
   acids (these are brominated by either addition or substitution
   reactions). With many of the metals and elements, anhydrous bromine is
   less reactive than wet bromine; however, dry bromine reacts vigorously
   with aluminium, titanium, mercury as well as alkaline earth metals and
   alkaline metals.

   Due to its contribution to ozone depletion in Earth's atmosphere,
   bromine has been evaluated to have an ozone depletion potential of 60
   when compared to chlorine.

Applications

   Elemental bromine is used to manufacture a wide variety of bromine
   compounds used in industry and agriculture. Traditionally the largest
   use of bromine was in the production of 1,2-dibromoethane which in turn
   was used as a gasoline anti- knock agent for leaded gasolines before
   they were largely phased out due to environmental considerations.

   Bromine is also used in the manufacture of fumigants, brominated
   flame-retardants, water purification compounds, dyes, medicines,
   sanitizers, inorganic bromides for photography, etc. It is also used to
   form intermediates in organic synthesis, where it is preferred to
   iodine due to its much lower cost.

   Bromine is used to make brominated vegetable oil, which is used as an
   emulsifier in many citrus-flavored soft drinks.

   Aqueous bromine is orange and can be used in tests for alkenes and
   phenols.
     * When added to an alkene it will lose its colour as it reacts
       forming a colorless bromoalkane. For example, reaction with
       ethylene will produce 1,2-dibromoethane.
     * When added to phenol a white precipitate, 2,4,6-tribromophenol,
       will form. With aniline, 2,4,6 tribromoaniline will precipitate
       (even in water)

History

   Bromine was discovered by Antoine Balard at the salt marshes of
   Montpellier in 1826 but was not produced in quantity until 1860. The
   French chemist and physicist Joseph-Louis Gay-Lussac suggested the name
   bromine due to the characteristic smell of the vapors.

Occurrence

   Bromine occurs in nature as bromide salts in very diffuse amounts in
   crustal rock. Due to leaching, bromide salts have accumulated in sea
   water (85 ppm), and may be economically recovered from brine wells and
   the Dead Sea (up to 5000 ppm).

   Approximately 500 million kilograms ($350 million USD) of bromine are
   produced per year (2001) worldwide with the United States and Israel
   being the primary producers. The largest bromine reserve in the United
   States is located in Columbia and Union County, Arkansas.

Safety

   Elemental bromine is a strong irritant and, in concentrated form, will
   produce painful blisters on exposed skin and especially mucous
   membranes. Even low concentrations of bromine vapor (from 10 ppm) can
   affect breathing, and inhalation of significant amounts of bromine can
   seriously damage the respiratory system.

   Accordingly, one should always wear safety goggles and ensure adequate
   ventilation when handling bromine.

Compounds

   Aluminium bromide (AlBr[3]), ammonium bromide (NH[4]Br), bromine
   monofluoride (BrF), bromine pentafluoride (BrF[5]), bromine trifluoride
   (BrF[3]), tetrabromomethane (CBr[4]), hydrobromic acid (HBr), iron(III)
   bromide (FeBr[3]), lithium bromide (LiBr), phosphorus pentabromide
   (PBr[5]), phosphorus tribromide (PBr[3]), potassium bromide (KBr),
   potassium bromate (KBrO[3]), silver bromide (AgBr), sodium bromide
   (NaBr), sodium bromate (NaBrO[3]).
   Retrieved from " http://en.wikipedia.org/wiki/Bromine"
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   with only minor checks and changes (see www.wikipedia.org for details
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