7 In presence of CN
–, (a strong ligand) the 3d electrons pair up leaving only one
unpaired electron The hybridisation is d
2sp
3 forming inner orbital complex In
the presence of H2O, (a weak ligand), 3d electrons do not pair up The
hybridisation is sp
3d
2 forming an outer orbital complex containing five unpaired
electrons, it is strongly paramagnetic