The configurations of the complexes of manganese $A$ and $B$ respectively are $t_{2g}^3 e_g^1$ and $t_{2g}^4 e_g^0$. Then $A$ and $B$ are:

The correct order of decreasing field strength of the below given ligands is

$I$. $NCS^{-}$	$II$. $S^{2-}$
$III$. $en$	$IV$. $SCN^{-}$

Explain the origin of colour in coordination compounds.

Using crystal field theory,draw energy level diagrams,write the electronic configuration of the central metal atom/ion,and determine the magnetic moment value for the following:
$(i)$ $[CoF_{6}]^{3-}, [Co(H_{2}O)_{6}]^{2+}, [Co(CN)_{6}]^{3-}$
$(ii)$ $[FeF_{6}]^{3-}, [Fe(H_{2}O)_{6}]^{2+}, [Fe(CN)_{6}]^{4-}$

The correct increasing order for the wavelengths of absorption in the visible region for the complexes of $Co^{3+}$ is:

Crystal field stabilization energy for high spin $d^4$ octahedral complex is