Question

IUPAC name for `[Fe(CN)_6]^(-4)` is? (A) hexacynoferrate (II) (B) hexacyno iron (II) (C) hexacynoferrate (IV) (D) hexacynoferrate (II) ion

Answer 1

Well IUPAC would probably call this `"hexacyanoferrate(II)"`

Explanation:

So `"option D"` is the one to order. I would simply call this `"ferrocyanide anion"`. This is clearly a salt of `Fe(II)` inasmuch as each of the cyanide ligands bears a formula negative charge:

`[Fe(C-=N)_6]^(4-)-=Fe^(2+) + 6xx""^(-):C-=N, "i.e. ferrous ion"`. Do the charges balance?

Note that in labs where cyanides are used extensively, there would be a bottle of Fe(II) salts at the ready, in order to force down the throat of someone who ingested cyanide thru mouth or hands.