Chemistry - Coordination Chemistry Question with Solution | TestHub

The smaller the ligand, the closer it comes to the metal ion and thus the greater the repulsion between ligand and the electrons present in the d-orbital of central atom that is why ${\mathrm{I}}^{-}<{\mathrm{Br}}^{-}<{\mathrm{Cl}}^{-}$ $<{\mathrm{F}}^{-}$are present in spectrochemical series as increasing ligand strength order.

Aminoethanethiolate complex of $\mathrm{Pt}(\mathrm{II}),\left[\mathrm{Pt}{\left({\mathrm{NH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{S}\right)}_2\right]$ has no enantiomers but has geometrical isomers while aminoethanethiolate complex of cobalt(II), $\left[\mathrm{Zn}{\left({\mathrm{NH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{S}\right)}_2\right]$ has no enantiomers and no geometrical isomers.

${\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$ is green, ${\left[\mathrm{Ni}{\left({\mathrm{NH}}_3\right)}_6\right]}^{2+}$ is deep blue and ${\left[\mathrm{Ni}(\mathrm{CN}{)}_4\right]}^{2-}$ is yellow because ${\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$ is absorbed red colour, ${\left[\mathrm{Ni}{\left({\mathrm{NH}}_3\right)}_6\right]}^{2+}$ is absorbed orange colour and ${\left[\mathrm{Ni}(\mathrm{CN}{)}_4\right]}^{2-}$ is absorbed violet indigo colour.

$\mathrm{Fe}(\mathrm{SCN}{)}_3$ with oxalates form optically inactive, colourless complex.