Phosphoric anhydride, when heated to low redness, burns with a pale flame in fluorine, forming a gaseous mixture of fluorides and oxyfluoride of phosphorus. Pentachloride and trichloride of phosphorus both react most energetically with fluorine, instantly producing a brilliant flame, and evolving a mixture of phosphorus pentafluoride and free chlorine.

Arsenious anhydride also affords a brilliant combustion, forming the liquid trifluoride of arsenic, AsF_{3}.  This liquid in turn appears to react with more fluorine with considerable evolution of heat, probably forming the pentafluoride, AsF_{5}. Chloride of arsenic, AsCl_{3}, is converted with considerable energy to the trifluoride, free chlorine being liberated.

Carbon bisulphide inflames in the cold in contact with fluorine, and if the fluorine is led into the midst of the liquid a similar production of flame occurs under the surface of the liquid, as in case of nitric acid.  No carbon is deposited, both the carbon and sulphur being entirely converted into gaseous fluorides.

Carbon tetrachloride, as previously mentioned, reacts only very slowly with fluorine.  The liquid may be saturated with gaseous fluorine at 15 deg., but on boiling this liquid a gaseous mixture is evolved, one constituent of which is carbon tetrafluoride, CF_{4}, a gas readily capable of absorption by alcoholic potash.  The remainder consists of another fluoride of carbon, incapable of absorption by potash and chlorine.  A mixture of the vapors of carbon tetrachloride and fluorine inflames spontaneously with detonation, and chlorine is liberated without deposition of carbon.

Boric anhydride is raised to a most vivid incandescence by fluorine, the experiment being rendered very beautiful by the abundant white fumes of the trifluoride which are liberated.

Silicon dioxide, one of the most inert of substances at the ordinary temperature, takes fire in the cold in contact with fluorine, becoming instantly white-hot, and rapidly disappearing in the form of silicon tetrafluoride.  The chlorides of both boron and silicon are decomposed by fluorine, with formation of fluorides and liberation of chlorine, the reaction being accompanied by the production of flame.

ACTION OF FLUORINE UPON METALLIC COMPOUNDS.

Chlorides of the metals are instantly decomposed by fluorine, generally at the ordinary temperature, and in certain cases, antimony trichloride for instance, with the appearance of flame.  Chlorine is in each case liberated, and a fluoride of the metal formed.  A few require heating, when a similar decomposition occurs, often accompanied by incandescence, as in case of chromium sesquichloride.

Bromides and iodides are decomposed with even greater energy, and the liberated bromine and iodine burn in the fluorine with formation of their respective fluorides.