Iron chloride FeCI

Definitely not Metal halides are by no means restricted to group 1 metals. In fact, most metals are able to form halides. Iron chloride, FeCI, and copper chloride, CuCi2, are examples. Figure 18.19 shows only the most common forms of metal compounds. In nature, iron is most commonly found as an oxide, while copper is most commonly found as a sulfide. 

The iron with a valence of 2 is referred to as ferrous in compounds (e.g., ferrous chloride = FeCy. When the valence is 3, it is called ferric (e.g., ferric chloride = FeCl ). 

Iron and chlorine react to form ironCIID chloride, FeCIs. 

Iron hahdes react with haHde salts to afford anionic haHde complexes. Because kon(III) is a hard acid, the complexes that it forms are most stable with F and decrease ki both coordination number and stabiHty with heavier haHdes. No stable F complexes are known. [FeF (H20)] is the predominant kon fluoride species ki aqueous solution. The [FeF ] ion can be prepared ki fused salts. Whereas six-coordinate [FeCy is known, four-coordinate complexes are favored for chloride. Salts of tetrahedral [FeCfy] can be isolated if large cations such as tetraphenfyarsonium or tetra alkylammonium are used. [FeBrJ is known but is thermally unstable and disproportionates to kon(II) and bromine. Complex anions of kon(II) hahdes are less common. [FeCfy] has been obtained from FeCfy by reaction with alkaH metal chlorides ki the melt or with tetraethyl ammonium chloride ki deoxygenated ethanol. 

The nomenclature of the compounds of the metals is also based upon their oxidation states. At the present time there are two principal nomenclatures in use. We may illustrate the two systems of nomenclature by taking the compounds FeCl2 and FeCla as examples. In the older system a compound of a metal in the lower of two important oxidation states is named by use of the name of the metal (usually the Latin name) with the suffix OHS. Thus the salts of iron in oxidation state -f2 are ferrous salts FeCl2 is called ferrous chloride. The compounds of a metal in the higher oxidation state are named with use of the suffix ic. The salts of iron in oxidation state -1-3 are called ferric salts FeCIs is ferric chloride. 

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