Definition of fluorine in English:



  • The chemical element of atomic number 9, a poisonous pale yellow gas of the halogen series. It is the most reactive of all the elements, causing severe burns on contact with skin.

    • ‘A hydrogen bond is a dipole dipole interaction that occurs between any molecule with a bond between a hydrogen atom and any of oxygen / fluorine / nitrogen.’
    • ‘Potassium also reacts readily with all acids and with many nonmetals, such as sulfur, fluorine, chlorine, phosphorus, and nitrogen.’
    • ‘The elements hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine and iodine consist of diatomic molecules.’
    • ‘As its position in the periodic table would suggest, it is less active than the three halogens above - fluorine, chlorine, and bromine.’
    • ‘The halogens are a group of chemical elements that includes fluorine, chlorine, bromine, iodine, and astatine.’


Early 19th century: from fluor (see fluorspar) + -ine.