Uses 1. Fluorine is used in the manufacture of a series of compounds known as freons. These non-toxic, non-combustible and volatile liquids are used as refrigerants in refrigerators, deep freezers and air conditioners. The most common, freon is known as dichlorodifluoro methane CF2 Cl2. 2. CaF2 is used as flux in metallurgy. 3. NaF is used as a preservative to prevent fermentation and also for preventing dental cavities. 4. SF6 is used as an insulating material in high voltage equipment. 5. Teflon is used as container to store hydrofluoric acid. 6. UF6 is used in the separation of U235 from U238. INTERHALOGEN COMPOUNDS OR INTERHALOGENS Each halogen combines with another halogen to form several compounds known as interhalogen compounds. The less electronegative element is written first. In naming also, the less electronegative element is mentioned first. They are divided into four types. AX
AX3
AX5
AX7
CIF BrF BrCl ICl IBr
ClF3 BrF3 ICl3
BrF5 IF5
IF7
They can all be prepared by direct combination or by the action of a halogen on a lower interhalogen, the product formed depends on the conditions. 473K
Cl2+ F2 (equal volume)
2ClF (AX type)
Ι2 + Cl2 liquid (equi molar) → 2ΙCl (AX type) Cl2 + 3F2 (excess)
573K
2 ClF3 (AX3 type)
Br2 + 3F2 (diluted with nitrogen)→ 2Br F3 Br2 + 5F2 (excess) → 2Br F5 (AX5 Type) 86