CoF3 Cobalt fluoride

As already noted, the simple salts in this oxidation state are powerful oxidising agents and oxidise water. Since, also, Co(III) would oxidise any halide except fluoride to halogen, the only simple halide salt is CoF3, Cobalt(lll) fluoride, obtained by reaction of fluorine with cobalt(II) fluoride it is a useful fluorinating agent. 

Co(en)2(N02)2]N03 cis- and trans-Dinitrobis(ethylenediamine)co-balt(III) nitrate, 4 176, 177 [Co(en)3]Cl3 Tris(ethylenediamine)-cobalt(III) chloride, 2 221 CoF3 Cobalt(III) fluoride, 3 175 [Co NH(C5H4N)21C12] Dichloro-(di-2-pyridylamine)cobalt (II), 6 184... 

Also, in anhydrous conditions, silver reacts with fluorine and forms silver difluoride AgF2 and cobalt gives cobalt(III) fluoride, CoF3, these metals showing higher oxidation states than is usual in their simple salts. 

Cobalt is a bluish silvery metal, exhibits ferromagnetism, and can exist in more than one crystal form it is used in alloys for special purposes. Chemically it is somewhat similar to iron when heated in air it gives the oxides Co304 and CoO, but it is less readily attacked by dilute acids. With halogens, the cobalt(II) halides are formed, except that with fluorine the (III) fluoride, CoF3, is obtained. 

Electrolytic oxidation of cobalt(II) fluoride in 40% hydrofluoric acid yields hydrated cobalt(III) fluoride, CoF3 3.5H20 (3.5 is the stoichiometric amount of water per C0F3 molecule in the crystal lattice). 

Cobalt(III) forms few simple salts, but the green hydrated fluoride CoF3-3.5H20 and the blue hydrated sulfate Co2(S04)3-18H20 separate on electrolytic oxidation... 

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