dibromine
CAS No.: 7726-95-6 Formula: Br2 Molecular Weight: 159.80800

dibromine

CAS No.: 7726-95-6 Formula: Br2 Molecular Weight: 159.80800
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Description

Bromine (from AncientGreek: βρῶμος, brómos, meaning "stench") is a chemical element with symbol Br and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826). Elemental bromine is a fuming red-brown liquid at room temperature, corrosive and toxic, with properties between those of chlorine and iodine. Bromine does not occur free in nature, but in colorless soluble crystalline mineral halide salts, analogous to table salt.
Bromine is rarer than about three-quarters of elements in the Earth's crust. The high solubility of bromide ions has caused its accumulation in the oceans, and commercially the element is easily extracted from brine pools, mostly in the United States, Israel and China. About 556,000 tonnes were produced in 2007, an amount similar to the far more abundant element magnesium.
At high temperatures, organobromine compounds readily convert to free bromine atoms, a process which has the effect of stopping free radical chemical chain reactions. This effect makes organobromine compounds useful as fire retardants; more than half the bromine produced industrially worldwide each year is put to this use. Unfortunately, the same property causes sunlight to convert volatile organobromine compounds to free bromine atoms in the atmosphere, and an unwanted side effect of this process is ozone depletion. As a result, many organobromide compounds that were formerly in common use—such as the pesticide, methyl bromide—have been abandoned. Bromine compounds are still used for purposes such as in well drilling fluids, in photographic film, and as an intermediate in the manufacture of organic chemicals.
Bromine has been long believed to have no essential function in mammals, but recent research suggests that bromine is necessary for tissue development. In addition, bromine is used preferentially over chlorine by one antiparasitic enzyme in the human immune system. Organobromides are needed and produced enzymatically from bromide by some lower life forms in the sea, particularly algae, and the ash of seaweed was one source of bromine's discovery. As a pharmaceutical, the simple bromide ion (Br−) has inhibitory effects on the central nervous system, and bromide salts were once a major medical sedative, before being replaced by shorter-acting drugs. They retain niche uses as antiepileptics.

Basic Info

Chemical Name dibromine
Synonyms

Bromine; Br2;

CAS No. 7726-95-6
Molecular Formula Br2
Molecular Weight 159.80800
PSA 0.00000
LogP 1.69120

Numbering system

UNII SBV4XY874G

Properties

Appearance & Physical State dark red liquid or reddish-brown gas
Density 3.119
Boiling Point 58.7ºC
Melting Point -7.2ºC
Flash Point 113ºC
Refractive Index 1.55
Water Solubility 35 g/L (20 ºC)
Stability Stable. Incompatible with reducing agents, alkali metals, powdered metals, steel, iron, copper, organic materials.
Storage Condition 2-8ºC
Vapor Density 7.14 (vs air)
Vapor Pressure 175 mm Hg ( 20 °C)

Safety Info

RTECS EF9100000
Hazard Class 8
Safety Statements S26-S45-S61-S7/9
HS Code 2801302000
Packing Group I
WGK Germany 2
RIDADR UN 1744
Risk Statements R26; R35; R50
Hazard Codes T+; C; N
Signal Word Danger
Hazard Declaration H314; H330; H400
Caution Statement P260; P273; P280; P284; P305 + P351 + P338; P310
Symbol GHS05, GHS06, GHS09
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