JEE Main 2022 — Chemistry Inorganic Chemistry

Complexes in which central atom has unpaired electrons is said to be paramagnetic in nature and where unpaired electrons are not present are diamagnetic in nature.

${[\mathrm{Fe}{(\mathrm{CN})}_{6}]}^{3-}$[Fe(CN)6​]3−, ${\mathrm{Fe}}^{+3}$Fe+3 $(3{d}^{5})\rightarrow {{t}_{2g}^{}}^{2,2}{{e}_{g}}^{1}$(3d5)→t2g​2,2eg​1, paramagnetic (one unpaired electron)

${[\mathrm{Fe}{(\mathrm{CN})}_{6}]}^{4-},{\mathrm{Fe}}^{+2}(3{d}^{6})\rightarrow {{t}_{2g}}^{6}{{e}_{g}}^{0}$[Fe(CN)6​]4−,Fe+2(3d6)→t2g​6eg​0 ,diamagnetic

${[\mathrm{Ti}{(\mathrm{CN})}_{6}]}^{3-},{\mathrm{Ti}}^{+3}(3{d}^{1})\rightarrow {{t}_{2g}}^{1}$[Ti(CN)6​]3−,Ti+3(3d1)→t2g​1 , Paramagnetic ($1$1 unpaired electron)

${[\mathrm{Ni}{(\mathrm{CN})}_{4}]}^{2-},{\mathrm{Ni}}^{+2}(3{d}^{8})\rightarrow$[Ni(CN)4​]2−,Ni+2(3d8)→ Diamagnetic

$${[\mathrm{Co}{(\mathrm{CN})}_{6}]}^{3-},{\mathrm{Co}}^{+3}(3{d}^{6})\rightarrow {{t}_{2g}}^{6},\mathrm{diamagnetic}$$[Co(CN)6​]3−,Co+3(3d6)→t2g​6,diamagnetic