Periodic Table

Bromine

Halogen

Quick Facts about Bromine

Se
  • liquid- state of matter at room temperature
  • Stable- has at least one stable isotope
  • +5, +1, -1- common oxidation states in compounds
  • ORC- crystal structure, atomic arrangement in solid form
Kr

Bromine (Br) is element 35 on the periodic table. Atomic mass of Br: 79.9040 u. Br is in period 4, group 17. Melting point of Br: 265.80 K.Density of Br: 3.10 g/cm³.

Why Bromine Matters

The only liquid nonmetal at room temperature—and it smells terrible

In Your Home

  • Fire retardants in furniture and electronics
  • Hot tub and pool sanitizers (bromine)
  • Some medications (sedatives historically)
  • Photography chemicals (historical)

Industry Uses

Fire SafetyBrominated flame retardants in plastics and textiles
AgricultureMethyl bromide fumigant (being phased out)
PharmaBromine-containing drugs for sedation and epilepsy
Water TreatmentPool and spa sanitation alternative to chlorine

In Your Body

✗ Not essential

Possibly essential in trace amounts (recent research). Historically used as sedatives. Bromide ions accumulate and cause 'bromism.'

Safety: Liquid bromine is corrosive and toxic. Vapors damage respiratory system. Bromide salts are less toxic but accumulate.

Discovery of Bromine

Discovered by Antoine J. Balard in France, 1826

Name origin: Greek: brômos (stench).

History & Events

1826
Discovery
Antoine Jérôme Balard discovered bromine in salt marsh water in France
1857
First Sedative
Potassium bromide introduced as first effective sedative medication
1987
Montreal Protocol
Methyl bromide targeted for phase-out due to ozone depletion

About Bromine

Halogen element. Red volatile liquid at room temperature. Its reactivity is somewhere between chlorine and iodine. Harmful to human tissue in a liquid state, the vapour irritates eyes and throat. Discovered in 1826 by Antoine Balard.

Atomic Properties of Br

Atomic Number of Br
35
Atomic Mass of Br
79.9040 u
Electron Configuration
[Ar] 3d10 4s2 4p5
Electronegativity
2.96
Block
p-block
Group
17
Period
4

Physical Properties of Br

Phase (STP)
liquid
Melting Point of Br
265.80 K
Boiling Point of Br
332.00 K
Density of Br
3.1028 g/cm3

Thermal Properties

Heat of Fusion
10.57 kJ/mol
Heat of Vaporization
29.56 kJ/mol
Specific Heat
0.47 J/g·K
Molar Heat Capacity
75.69 J/mol·K
Thermal Conductivity
0.01 W/m·K

Atomic Radii

Calculated
115 pm
Covalent
114 pm
Van der Waals
185 pm

Common Misconceptions

Wrong:Bromine is safe because it's in pools.
Correct:Pool bromine is diluted bromide compounds. Elemental bromine is highly toxic and corrosive.
Wrong:'Bromide' just means a boring statement.
Correct:This meaning comes from bromide sedatives making people dull and drowsy in the 1800s.
Wrong:Bromine is rare.
Correct:Bromine is common in seawater (65 ppm) and salt deposits. It's extracted commercially.

Isotopes of Bromine

Bromine has 2 naturally occurring isotopes, plus 2 notable radioactive isotopes.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
7535Br (Br-75)Bromine-75 isotope74.9257760%96.7 minutesβ⁺, EC
7735Br (Br-77)Bromine-77 isotope76.9213790%57.04 hoursβ⁺, EC
7935Br (Br-79)Bromine-79 isotope78.918337650.69%
8135Br (Br-81)Bromine-81 isotope80.916289749.31%

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Bromine have important real-world applications in science and industry.

Medical Applications

77Br (with a half-life of 57 h) is used to label radiopharmaceuticals that bind to estrogen receptors for tumor imaging. 75Br (with a half-life of 97 min) is being used with positron emission tomography (PET) imaging [281].

Abundance

Earth's Crust
2.4 mg/kg
Seawater
67.3 mg/L

Uses

It was once used in large quantities to make a compound that removed lead compound build up in engines burning leaded gasoline. Now it is primarily used in dyes, disinfectants, and photographic chemicals.

Sources

Occurs in compounds in sea water.

Geochemistry

Goldschmidt
litophile
Geochemical Class
semi-volatile

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