Explain tetrahedral Ni (II) complexes are Paramagnetic but squaire planar Ni (II) complexes are diamagnetic.

in tetrahedral complexes pairing of electrons does not occur so they are paramagnetic whereas in square planar complexes one inner d orbital is used that's why pairing occurs so they are dimagnetic.

in tetrahedral complexes the last 2 electrons in the d-sub shell remain unpaired while in the square planar complexes these two electrons are paired into one subshell so hat the last d-orbital is vacant to hybridize Therefore square planar complexes are diamagnetic.