Bromine

bromine

Bromine is the only non-metallic element that is liquid at room temperature. Its thick vapors emitted by this liquid are dangerous if inhaled. Pure bromine is never found in nature. Moreover, its compounds can easily mix in water, and are found dissolved in seawater and extremely salty lakes, such as the Dead Sea in the Middle East. Solid bromine salts, including potassium bromide, KBr, accumulate as water evaporates. This promotes the formation of white crystal crusts, from which bromine can be extracted. A common use of this element is as a disinfectant to clean water. It works better than chlorine in hot tubs, as the chlorine easily escapes into the air from the hot water. The concentration of bromine in pools can be regulated by chemical test kits. Bromine compounds can be used in film photography where images are printed using chemicals on negatives. Today, bromine is mainly used in flame-retardant materials, such as firefighting suits or furniture, as it does not catch fire easily.

Summary of properties (Br)

Atomic weight[79.901, 79.907]
Discoverer (year)Balard, Antoine-Jérôme (1826)
Natural formliquid (Br2)
Electron configuration[Ar] 3d10 4s2 4p5
Melting point (ºC)-7
Boiling point (ºC)58.8
Abundance in earth's crust (ppm)2.4
Isotope (abundance)79Br (50.69), 81Br (49.31)
Density g/cm33.12
Van der Waals radius (pm)185
Covalent radius (pm)117
Electronegativity (Pauling)
Vaporization enthalpy (kJ/mol)29.96
Enthalpy of fusion (kJ/mol)10.57
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.23
Thermal conductivity (W/cm·K) at 25ºC and 1 atm0.001 (Br2)
Oxidation state+5, +1, -1
Electron affinity (eV)3.36
1st Ionization potential (eV)11.8138

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