In periodic table, a group of elements is referred to as the halogen. This group contains iodine, fluorine, chlorine and astatine along with bromine. The atomic number of bromine is 35 and its atomic weight is 79.90 amu. It is a unique element in the periodic table, in the sense, that it is the only non-metallic element found in the liquid form at room temperature. Bromine is known to be harmful to humans as it can affect eyes, skin and the respiratory tract and needs a lot of careful handling.
Applications of Bromine
In its liquid form, bromine is reddish-brown in color. Its vapors give off a pungent smell and are reddish in color. It was found that bromine is more soluble in carbon disulfide and solvents, like methanol and acetic acid than in the water. It needs only one electron to complete an octet of electron in its outermost shell. This enables it to take part in various chemical reactions and act as a strong oxidizing agent.
In Fire Retardant Chemicals
One of the important bromine applications is in manufacturing brominated flame retardants. These are used as chemical flame retardants in the plastic industry and in products, such as cables, connectors, plastic covers. Bromine's flame retardant property, is also employed to make products, like carpets, upholstery, paints and kitchen appliances safe. It is also used in the clothing and furniture industries, to prevent the products from catching fire. In the electronics industries, especially in computers, it is used to make fireproof printed circuit boards. Polybrominated diphenyl ether, polybrominated biphenyl, decabromodiphenyl ether, hexabromocyclododecane, tetrabromobisphenol are few of the examples of flame retardant chemicals that are made using bromine.
As a Disinfectant
Bromine is a bleaching agent, and is used to disinfect water in cooling towers and the swimming pools. In this case, bromine test strips are used to detect phenols and unsaturated double bond compounds as well as alkalinity, pH and hardness of water. In hospitals and commercial industries and homes, it is manly used as a sanitizer and a germicide to neutralize bacteria, algae and fungi. It is also employed as a sanitizer, in areas where there is less or no chances of it coming in contact with food. Bromine is also preferred for disinfection of industrial water.
In Water Purification Compounds
You can find bromine in products that are used in water purification systems. Tralomethrin is one such product used to purify drinking water. The amount of bromine present in water should not be more than 100mg/deciliter, which is its lowest toxic level. If found in quantities higher than these, bromine can prove to be harmful.
Bromine is also used in agricultural products such as pesticides to destroy pests. It is most preferred to get rid of pests which targets crops, such as potatoes, tomatoes, etc. Methyl bromide, is a chemical compound that acts as a fumigate. It is used to protect stored grains and other produces by destroying pests.
In Photography Film
The most well-known use of bromine, is in making photographic films. Silver bromide is light-sensitive and is used to manufacture photography plates. Its microscopic particles when exposed to light, undergo a change as a result of chemical reaction. This property of silver bromide is responsible for the production of the image, when the photographic film is exposed to light when you click the shutter. Potassium bromide is used in photography, to prevent undesired reduction of silver, which causes fogging in a photograph.
Bromine has been used as a drug, for a long time, in one or the other form. Primarily, chemical compounds derived from it are used as oral sedatives, to treat epilepsy and as diuretics. It is well-known for its central nervous system depressive role in bromide poisoning. In the past, as late as the start of 20th century, potassium bromide was used as a preferred sedative. Bromo-Seltzer, is another product that was in use till 1975, before it was discontinued by FDA.
It was in 1909, when a German chemist Paul Friedländer found that the Tyrian purple dye (red-purple to deep purple) contains bromine. In this form, it was known to man for hundreds of years. Tyrian purple dye is nothing but a chemical 6,6'-dibromoindigo. Another such dye used is tetrabutylammonium bromide. There are many other applications in the textile industry.
- Salts of bromine formed with calcium, sodium, and zinc are water-soluble. The dense solution thus, formed is used as a drilling fluid while drilling boreholes.
- Ethidium bromide or EtBr is used as a DNA stainer, in the process of gel electrophoresis. Normally this chemical, under ultraviolet light, gives out orange-glow which intensifies, if EtBr binds with a DNA.
- Bromine is employed to reduce mercury pollution that the coal consuming power plants cause. Activated carbon and coal treated with bromine, does the trick.
- 5-bromouracil, is used as an artificial mutagen which helps scientists in forcing the genetic materials, such as, DNA to change.
Though it is known that the bromine does not harm immediately on contact, prolonged exposure to it may lead to thyroid gland dysfunction. It can hamper iodine levels in the body, exposing an individual to risk of cancer. Individuals with abnormal thyroid function should choose organic food, as many of the foods are treated with compounds of bromine. Same goes for water, as many a time, it is treated with bromine. Bakery products, toothpaste that use potassium bromate as well as citrus drinks that contains brominated vegetable oils are best avoided. It also pays to know the fire-retardant chemicals used in items such as, computers, plastics, carpets, automobiles, etc. Check the label on healthcare products such as nasal sprays and inhalers to know they are free of bromine.
Bromine is a very useful element, as can be seen from its applications presented above. You can find it in primary industry, such as agriculture, to products that are used for recreation, such as photography. The industries like pharmaceuticals and dyeing, also use chemicals that are derived from bromine.