Bromine is a chemical element which is a member of the halogen family, along with fluorine, chlorine, iodine, and astatine. In the periodic table, it is placed in group 7, between chlorine and iodine. In chemistry, it is denoted by the symbol 'Br'. It was discovered in the year of 1826. Interestingly, two scientists isolated the element at the same time, but they were working independently. This nonmetallic element derived its name from the Greek word 'bromos', that means stench. It is well-known that bromine has a strong and irritating odor.
The physical and chemical properties of bromine are unique compared to other elements. Few such important characteristics of this element are as follows.
- Elemental bromine can be identified as a thick liquid, with a reddish-brown color, and having a strong odor. In fact, it is the only nonmetal in the periodic table that can be found in a liquid state at room temperature, although, it is quite volatile in nature, and readily changes into a red vapor with a pungent smell.
- Bromine is abundantly found in nature, but, not in a free state. It is usually available in the form of bromide salts. These salts are highly soluble in water, and get accumulated in various water bodies. Due to this fact, the main source of bromine is seawater, from which, it is extracted for commercial uses. The US, Israel, and China are the highest producers in volume of this chemical element.
- Its atomic number is 35 and its atomic mass is 79.90. The number of electrons per shell is: 2, 8, 18, and 7 respectively. As the electron distribution of the element suggests, it requires just one electron to complete the octet in its outermost shell. For this reason, in its pure form, bromine is largely found as a diatomic molecule, with the formula Br2.
- Bromine dissolves in water, but, it has a higher solubility in various organic solvents, such as methanol, carbon disulfide, aliphatic alcohols, acetic acid, etc.
- As compared to other halogens, like fluorine or chlorine, it is slightly less reactive in nature. Owing to its strong oxidizing properties, it reacts with metals quite vigorously, particularly, if it takes place in the presence of water, to form bromide salts. It also shows high reactivity towards organic compounds, especially, under favorable light conditions.
Bromine was discovered in 1826, and its extraction on a large scale began only in 1860, although, its usage had started much before. A purple-colored excretion obtained from specific mollusks was used as a dye, but nobody knew at that time that it was a bromine compound. Today, bromine and its compounds have many other important uses. It has excellent bleaching properties, and is used as a disinfectant in swimming pools. It is used for producing brominated vegetable oil, which is added to citrus flavored soft drinks.
A major industrial application of this element is in the manufacturing of brominated flame retardant. It consists of hydrobromic acid, which, as the name suggests, is made up of hydrogen and bromine. It plays a major role in blocking the reaction between oxygen and fire, and helps to control the flame. Several bromide compounds are used as a component in water purification devices, clothing dyes, flame retardants in plastics, drilling fluids, etc. Potassium bromide is widely used for the purpose of photographic development. Here, it serves as a source of bromide ions, that are needed for producing silver bromide, which is then used for photographic films.
Bromine is toxic in nature, and causes skin irritation when it comes in direct contact with the skin. Therefore, it should be handled with great care. Still, if you get exposed to it accidentally, then you must have a proper bath, and visit a doctor immediately.