Applications of coordination compounds

$cis\text{-}[PtCl_2(NH_3)_2]$ (cisplatin) is used as an anticancer agent.

The red precipitate is bis(dimethylglyoximato)nickel(II).
Each dimethylglyoximate ion binds through its two nitrogen atoms (bidentate), and the two ligands are held together by symmetrical O–H···O hydrogen bonds.
$Ni^{2+}$ ($d^8$) is $dsp^2$ hybridised here, so the complex is square planar and diamagnetic.

So the statement that it has a tetrahedral geometry is not true.