BROMINE

Bromine was discovered independently by two chemists, carl jacob lowig and antoine balard. Lowig isolated bromine from a mineral water spring which was situated in his hometown. Lowig used a solution of the mineral salt saturated with chlorine and and extracted the bromine with diethyl ether. After evaporation of the ether a brown liquid remained which was used as a sample of his work. Balard found bromine chemicals in the ash of seaweed from the salt marshes of Montpellier. The seaweed was used to produce iodine, but also contained bromine. Balard distilled the bromine from a solution of seaweed ash saturated with chlorine. The properties of the resulting substance were intermediate between those of chlorine and iodine; thus he tried to prove that the substance was iodine monochloride (ICl), but after failing to do so he was sure that he had found a new element, and named it muride, derived from the Latin word muria for brine.
After the French chemists Louis Nicolas Vauquelin, Louis Jacques Thénard, and Joseph-Louis Gay-Lussac approved the experiments of the young pharmacist Balard, the results were presented at a lecture of the Académie des Sciencesand published in Annales de Chimie et Physique. In his publication, Balard states that he changed the name from muride to brôme on the proposal of M. Anglada. Brôme (bromine) derives from the Greek βρωμος (stench). Other sources claim that the French chemist and physicist Joseph-Louis Gay-Lussac suggested the name brôme for the characteristic smell of the vapors. Bromine was not produced in large quantities until 1858, when the discovery of salt deposits in Stassfurt enabled its production as a by-product of potash.


Bromine is a chemical element with symbol Br and atomic number 35. It is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured gas. Its properties are thus intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived from the Ancient Greek βρῶμος ("stench"), referencing its sharp and disagreeable smell




The Hunsdiecker reaction (also called the Borodin reaction or the Hunsdiecker–Borodin reaction) is a name reaction in organic chemistry whereby silver salts of carboxylic acids react with a halogen to produce an organic halide.[1] It is an example of both a decarboxylation and a halogenation reaction as the product has one fewer carbon atoms than the starting material (lost as carbon dioxide) and a halogen atom is introduced its place. The reaction was first demonstrated by Alexander Borodin in his 1861 reports of the preparation of methyl bromide from silver acetate.[2][3] Shortly after, the approach was applied to the degradation of fatty acids in the laboratory of Adolf Lieben.[4][5] However, it is named for Cläre Hunsdiecker and her husband Heinz Hunsdiecker, whose work in the 1930s[6][7] developed it into a general method.[1] Several reviews have been published,[8][9] and a catalytic approach has been developed.[10]
 
 Occurrence in nature
 
 Bromine is too reactive to exist as a free element in nature. Instead, it occurs in compounds, the most common of which are sodium bromide (NaBr) and potassium bromide (KBr). These compounds are found in seawater and underground salt beds. These salt beds were formed in regions where oceans once covered the land. When the oceans evaporated (dried up), salts were left behind—primarily sodium chloride (NaCl), potassium chloride (KCl), and sodium and potassium bromide. Later, movements of the Earth's crust buried the salt deposits. Now they are buried miles underground. The salts are brought to the surface in much the same way that coal is mined.
Bromine is a moderately abundant element. Its abundance in the Earth's crust is estimated to be about 1.6 to 2.4 parts per million. It is far more abundant in seawater where it is estimated at about 65 parts per million.
In some regions, the abundance of bromine is even higher. For example, the Dead Sea (which borders Israel and Jordan), has a high level of dissolved salts. The abundance of bromine there is estimated to be 4,000 parts per million. The salinity, or salt content, is so high that nothing lives in the water. This is why it is called the Dead Sea.


Isotopes


Two naturally existing isotopes of bromine exist, bromine-79 and bromine-81. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope.
At least 16 radioactive isotopes of bromine are known also. A radioactive isotope is one that breaks apart and gives off some form of radiation. Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive.
No isotope of bromine has any important commercial use.
The salinity, or salt content, is so high that nothing lives in the water. This is why it is called the Dead Sea.