Answer
Potassium hexacyanomanganate(II)
Work Step by Step
1. In $K_{4}[Mn(CN)_{6}]$, $K_{4}$ is the cation whereas $[Mn(CN)_{6}]$ is the anion. Cations are named first then are anions. When the complex is the anion, its name has -ate at the end.
2. In order to name the anion, Ligand is named first then is the metal. Thus, since six Cyanide ions are present: hexacyano
3. Mn is Manganese but since the complex is an anion, its named as Manganate.
4. In order to write the charge on the metal, we add the charges and equal it to the charge on the complex, in this case zero. Potassium has +1 charge and cyanide has a -1 charge.
Thus,
$4\times (+1) +x +6 (-1) =0$
$+4+x-6=0$
$x=+6-4$
$x=+2$
Thus the charge is +2 on the metal. Hence,
the name of the complex is Potassium hexacyanomanganate (II)
