Significance Of Halogen In Nature

Group VIIA, the next-to-last column of the periodic table, contains six elements. As one might imagine, these elements share several characteristics. They all form diatomic molecules (H2, F2, Cl2, Br2, I2, and At2) and negatively charged ions (H-, F-, Cl-, Br-, I-, and At-).

When discussing the chemistry of these elements, hydrogen is distinguished from the others, while astatine is overlooked due to its radioactivity. (The half-lives of the most stable astatine isotopes are less than a minute.) As a result, the largest samples of astatine molecules investigated to date were fewer than 50 ng.) The chemistry of Group VIIA elements is thus concentrated on four elements: fluorine, chlorine, bromine, and iodine. The halogens are named by the fact that they are salt-forming elements.

In their elemental state, none of the halogens can be found in nature. They are almost always encountered as halide ion salts (F-, Cl-, Br-, and I-). Minerals like fluorite (CaF2) and cryolite contain fluoride ions (Na3AlF6). Chloride ions can be found in rock salt (NaCl), the oceans (which include about 2% Cl- ion by weight), and salty lakes (such as Utah’s Great Salt Lake, which has 9 percent Cl- ion by weight).

The Elemental Form of the Halogens:

Fluorine:

Fluorine (F2) is a very toxic, colourless gas that is the most reactive element known, igniting asbestos, water, and silicon when it comes into contact with it. It’s so reactive that it forms compounds with elements like Kr, Xe, and Rn, which were once thought to be inert.Fluorine is so reactive that finding a container in which it may be stored is difficult. F2 affects glass and quartz, for example, as well as most metals, causing them to catch fire. Equipment made of copper and nickel alloys is used to manage fluorine. It reacts with these alloys as well, but it generates a fluoride coating on the surface that protects the metal from further reaction.

Chlorine (Cl2) is an extremely poisonous gas that has a pale yellow-green appearance. Chlorine is a highly strong oxidising chemical that is utilised as a bleaching agent and disinfectant in industry. It’s powerful enough to oxidise the dyes that give wood pulp its yellow or brown colour, bleaching out the hue, and powerful enough to kill germs, acting as a germicide. Each year, a large amount of chlorine is needed to create solvents such carbon tetrachloride (CCl4), chloroform (CHCl3), dichloroethylene (C2H2Cl2), and trichloroethylene (C2H2Cl2) (C2HCl3).

Bromine (Br2) is a suffocating reddish-orange liquid with an awful odour. This element’s name comes from the Greek term  bromos, which means “stench.” Flame retardants, fire-extinguishing agents, sedatives, antiknock agents for gasoline, and insecticides are all made with bromine.

Iodine is a brightly coloured solid with a nearly metallic sheen. This substance is relatively flammable, and when heated, it transforms into a violet-colored gas. Iodine has been used as a disinfectant in “tincture of iodine” for many years. Catalysts, medicines, and colours are all made from iodine compounds. Silver iodide (AgI) is used in the photography process as well as in cloud seeding attempts to generate rain. Iodide is frequently added to salt to prevent goitre, which is an iodine deficient illness characterised by thyroid gland swelling.

oxidising strength: F2 > Cl2 > Br2 > I2

The chemistry of the halogens follows  patterns like:

1. The chemistry of the halogens can be explained without the use of double or triple bonds.
2. Fluorine’s chemistry is simplified by the fact that it is the most electronegative element in the periodic table and that it has no d orbitals in its valence shell, preventing it from expanding.
3. Valence shell d orbitals exist in chlorine, bromine, and iodine, and they can expand their valence shells to house up to 14 valence electrons.
4. Oxidation-reduction processes dominate the chemistry of the halogens.

Uses:

Chemical, water and sanitation, plastics, pharmaceutical, pulp and paper, textile, military, and oil industries all utilize halogens. Chemical intermediates, bleaching agents, and disinfectants include bromine, chlorine, fluorine, and iodine. 

In the textile business, both bromine and chlorine are used to bleach and shrink-proof wool. Bromine is also employed in the extraction of gold and in the drilling of oil and gas wells. It’s used in the plastics sector as a fire retardant and as an intermediary in the production of hydraulic fluids, refrigerating and dehumidifying agents, and hair-waving preparations. Bromine can also be found in military gas and firefighting fluids.

Conclusion: 

Halogens, such as chlorine or bromine, pose a health risk to the lungs and other organs in the environment and at work. Chlorine causes dyspnea, hypoxemia, airway blockage, pneumonitis, pulmonary edema, and acute respiratory distress syndrome when inhaled (ARDS). Inhalation of bromine causes bronchospasm, airway hyperresponsiveness, ARDS, and even mortality, despite the fact that it is less reactive and oxidative than chlorine. Both halogens have been demonstrated to wreak havoc on the circulatory system and cause heart damage. Because the processes are mostly understood, there is no specific antidote for these injuries.