Noun
A non-metallic, gaseous element, strongly acid or negative, or associated with chlorine, bromine, and iodine, in the halogen group of which it is the first member. It always occurs combined, is very active chemically, and possesses such an avidity for most elements, and silicon especially, that it can neither be prepared nor kept in glass vessels. If set free it immediately attacks the containing material, so that it was not isolated until 1886. It is a pungent, corrosive, colorless gas. Symbol F. Atomic weight 19.
Source: Webster's dictionaryAddition of fluorine and chlorine usually results in a flattening of the C 60 framework into a drum-shaped molecule. Source: Internet
All of the ozone depleting substances controlled by the Montreal Protocol contain either chlorine or bromine (substances containing only fluorine do not harm the ozone layer). Source: Internet
Characteristics Chemical The halogens show trends in chemical bond energy moving from top to bottom of the periodic table column with fluorine deviating slightly. Source: Internet
Because the fluorine and chlorine atoms differ greatly in size and effective charge from hydrogen and from each other, the methane-derived CFCs deviate from perfect tetrahedral symmetry. Source: Internet
A total of 31 isotopes of astatine have been discovered, with atomic masses ranging from 193 to 223. Production Approximately six million metric tons of the fluorine mineral fluorite are produced each year. Source: Internet
As a consequence, the most common halogen substitutions are the less reactive aromatic fluorine and chlorine groups. Source: Internet