![]() ![]() In 1860, George Gore, an English chemist, ran a current of electricity through hydrofluoric acid and probably produced fluorine, but he was unable to prove his results at the time. Early chemists realized that fluorine compounds contain an undiscovered element, but were unable to isolate it. The fluorine mineral fluorospar was known as early as 1529. ![]() Organobromides are the most important class of flame retardants, while elemental halogens are dangerous and can be toxic. The middle halogens-chlorine, bromine, and iodine-are often used as disinfectants. ![]() Most halogens are typically produced from minerals or salts. All of the halogens form acids when bonded to hydrogen. The group of halogens is the only periodic table group that contains elements in three of the main states of matter at standard temperature and pressure, though not far above room temperature the same becomes true of groups (I) and 15, assuming white phosphorus is taken as the standard state. When halogens react with metals, they produce a wide range of salts, including calcium fluoride, sodium chloride (common table salt), silver bromide and potassium iodide. The word "halogen" means "salt former" or "salt maker". In the modern IUPAC nomenclature, this group is known as group (XVII) or group (VII). The halogens ( / ˈ h æ l ə dʒ ə n, ˈ h eɪ-, - l oʊ-, - ˌ dʒ ɛ n/ ) are a group in the periodic table consisting of six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts), though some authors would exclude tennessine as its chemistry is unknown and is theoretically expected to be more like that of gallium. ![]()
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