The halogens - also known as elemental gases - are based on a group of five chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and radioactive astatine (At), all of which form acids when bonded to hydrogen.
Most halogens are typically produced from minerals or salts. The middle halogens, chlorine, bromine and iodine, are often used as disinfectants. All of the halogens are toxic.
All of the halogens react (F, Cl, Br) explosively with hydrogen to form hydrogen halides (e.g. HF, HCl, HBr, HI) and all forms acid wihen mixed with water. All of the hydrogen halides are irritants. Hydrogen fluoride and hydrogen chloride are highly acidic.
Hydrogen halides are formed during combustion of halogen-containing organic compounds.
|colourless, non-flammable, toxic gas with a pungent smell. Very soluble in water, forming hydrochloric acid and thus a highly corrosive fog in wet air.||HCI|
|colourless, non-flammable, toxic gas with an acrid odor. Very soluble in water, forming strongly acidic hydrobromic acid.||HBr|
|colourless, non-flammable, very toxic gas with a pungent smell. Miscible with water, forming acidic hydrofluoric acid.||HF|
|colourless, non-flammable, corrosive gas with a pungent smell. Very soluble in water, forming strongly acidic hydroiodic acid||HI|