Stannic Fluoride or tin(iv) fluoride, is an inorganic tin fluoride compound, and generally a off-white powder. It is hygroscopic and has a melting point of 700 C or higher, well above the melting points of other tin(iv) halides.
It is used as Friedel-Crafts catalyst.
Stannic fluoride can be prepared from the reaction of fluorine, chlorine trifluoride, or bromine trifluoride with tin(II) or tin(IV) compounds. It acts as a Lewis acid to form many complexes. It is used in the manufacture of glasses.
Stannic fluoride combines with ammonia and other bases, and also with alkali and other fluorides to form stannifluorides of the type M2SnF6. Stannic fluoride forms with ammonia at 43° C. the white solid SnF4.NH3, which can be heated to 400° C. with loss of very little ammonia; the compound SnF4.2NH3 is formed when stannic fluoride and ammonia are heated in a sealed tube at 120°-130° C. Both compounds dissolve in water, but their solutions gradually decompose. Aniline, pyridine, and quinoline also form additive compounds with stannic fluoride.
