The oxidation number of cobalt in K[Co(CO)4] is
Oxidation number of Co: K[Co(CO)4] x+(4×0)=−1;x=−1
(i) +1
(ii) +3
(iii) −1
(iv) −3
Oxidation number of cobalt in K[Co(Co)4] is
Oxidation number of cobalt in [Co(NH3)6]Cl2Br is: