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Bromine

Selenium - Bromine - Krypton
Cl
Br
I  
 
 
General
Name, Symbol, NumberBromine, Br, 35
Series Halogens
Group, Period, Block17 (VIIA), 4 , p
Density, Hardness 3119 kg/m3 (300 K), NA
Appearance Gas: red-brown
solid: metallic luster
Atomic Properties
Atomic weight 79.904 amu
Atomic radius (calc.) 115 (94) pm
Covalent radius 114 pm
van der Waals radius 185 pm
Electron configuration [Ar]33d10 4s24p5
e- 's per energy level2, 8, 18, 7
Oxidation states (Oxide) ±1,5 (strong acid)
Crystal structure Orthorhombic
Physical Properties
State of matter liquid (nonmagnetic)
Melting point 265.8 K (19 °F)
Boiling point 332 K (138 °F)
Molar volume 19.78 ×1010-3 m3/mol
Heat of vaporization 15.438 kJ/mol
Heat of fusion 5.286 kJ/mol
Vapor pressure 5800 Pa at 280.1 K
Speed of sound 206 m/s at 293.15 K
Miscellaneous
Electronegativity 2.96 (Pauling scale)
Specific heat capacity 480 J/(kg*K)
Electrical conductivity no data
Thermal conductivity 0.122 W/(m*K)
1st ionization potential 1139.9 kJ/mol
2nd ionization potential 2103 kJ/mol
3rd ionization potential 3470 kJ/mol
4th ionization potential 4560 kJ/mol
5th ionization potential 5760 kJ/mol
6th ionization potential 8550 kJ/mol
7th ionization potential 9940 kJ/mol
8th ionization potential 18600 kJ/mol
Most Stable Isotopes\
isoNAhalf-life DMDE MeVDP
79Br50.69%Br is stable with 44 neutrons
81Br49.31%Br is stable with 46 neutrons
SI units & STP are used except where noted.
Bromine 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 room temperature which has a reactivity between chlorine and iodine. This element is harmful to human tissue in a liquid state and its vapour irritates eyes and throat.

Notable Characteristics

Bromine is the only liquid nonmetallic element at room temperature. It is a heavy, mobile, reddish-brown liquid, that evaporates easily at standard temperature and pressures in a red vapor (its color resembles nitrogen dioxide) that has a strong disagreeable odor. A halogen, bromine resembles chlorine chemically but is less active (it is more active than iodine however). Bromine is very soluble in water or carbon disulfide (forming a red solution). 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). With many of the metals and elements, anhydrous bromine is less reactive than wet bromine; however, dry bromine reacts vigorously with aluminum, titanium, mercury as as well as alkaline earth and alkaline metals.

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 ethylene dibromide 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 making fumigants, flameproofing agents, water purification compounds, dyes, medicinals, sanitizes, inorganic bromides for photography, etc.

History

Bromine (Gr bromos for stench) was discovered by Antoine Balard in 1826 but was not produced in quantity until 1860.

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.

Precautions

Elemental bromine is highly toxic, and touch or breathing more than trace amounts (10 ppm) can cause immediate health problems or death. Bromine is very irritating to both eyes and throat produces painful sores after making contact with skin. Improper handling of this element can be a serious health hazard requiring maximum safety precautions.

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