- 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.
Definition
[ n.]