Using valence bond theory predict the geometry and magnetic behaviour of `[Pt(CN)_4]^(2-)`.

Explanation

`""_(78)Pt` lies in Group 10 with the ground state outer electronic configuration `5 d^9 6 s^(1)`. Hence `Pt^(2+)` has the configuration `d^8`. X-ray studies have shown that the complex has a square planar shape. For square planar shape, the hybridisation is `dsp^2`. Hence, the unpaired electrons in 5 d pair up to make one d-orbital empty for `dsp^2`-hybridization. It is also supported by the fact that `CN^(-)` a strong ligand can pair up the unpaired delectrons. Thus, there is no unpaired electron and the complex is diamagnetic.

Geometry : Square planar , Hybridisation : `dsp^2`, Magnetic Character : Diamagnetic. It is inner orbital or low spin complex.