પરમાણુ ભાર : $Mn = 25,\,Fe = 26,\,Co = 27,\,Ni = 28$
$(i) [pt\ (en)\ Cl_2]$
$(ii)\ [pt (en)_2]\ Cl_2$
$ (iii)\ [pt (en)_2 Cl_2]\ Cl_2$
$(iv)\ [pt (CH_3)_2 Cl_2]$
${\left[ {V\,{{\left( {CN} \right)}_6}} \right]^{4 - }}$ , ${\left[ {Fe\,{{\left( {CN} \right)}_6}} \right]^{4 - }}$ , ${\left[ {Ru\,{{\left( {N{H_3}} \right)}_6}} \right]^{3 + }}$ , અને ${\left[ {Cr\,{{\left( {N{H_3}} \right)}_6}} \right]^{2 + }}$
$A: \left[ Ni ( en )_{3}\right]^{2+}, B :\left[ Ni \left( NH _{3}\right)_{6}\right]^{2+}, C :\left[ Ni \left( H _{2} O \right)_{6}\right]^{2+}$