The oxidation number of iron in the compound $K_4[Fe(CN)_6]$ is

Which is the correct formula for the pentaamminecarbonatocobalt$(III)$ chloride coordination compound?

What is the $IUPAC$ name of $[CoCl_{2}(en)_{2}]^{+}$?

The $IUPAC$ name of the complex $\left[ Ag(H_{2}O)_{2} \right] \left[ Ag(CN)_{2} \right]$ is :

Provide the $\text{IUPAC}$ names for the following coordination compounds:
$(i)$ ${K_2}[Zn(Cl)_4]$
$(ii)$ ${K_4}[Fe(CN)_6]$
$(iii)$ $[Co(NH_3)_4Cl_2]Cl$
$(iv)$ $[Fe(NH_3)_6]^{3+}$

The correct $IUPAC$ name of the complex $Hg[Co(CNS)_4]$ is ........