Naming question

[Shaleena 3C]

Name each of the following complex ions and identify the oxidation number of the metal:

(a) [Fe(CN)6]4-

(b) [Co(NH3)6]3+

(c) [CO(CN)5(OH2)]2-

(d) [Co(NH3)5(SO4)]+

Doing some practice questions and need a bit of help with this one :) a detailed rundown would be appreciated.

[305749341]

a) hexa cyano iron (II)
Ligand name before the transition metal ion and use a prefix to indicate the number of ligands. There are 6 ligands of cyanide so the prefix is hexa-. Add O to the end of anion name (cyanide >> cyano). Then transition metal cation name and the oxidation state. CN has a -1 oxidation state and since there are six it is -6. Since the overall charge of compound is -4 then iron has an oxidation state of +2 (roman numeral II).

b) hexa ammine cobalt (III)
6 ammonia gives the prefix hexa
Ammonia when forming bond with transmition metal >> ammine
Ammine is neutral, overall charge is +3 >> cobalt oxidation state is +3 (roman numeral III)

c) penta cyano dihydroxo cobalt (V)
same pattern as above, but now there are two ligands >> but them in alphabetical order

d) penta ammine sulfato cobalt (III)