Which of the following statements about the nickel dimethylglyoximate complex, $[Ni (DMG) X_{2}]$ , are correct?

AThe complex is square planar with nickel in the $+ 2$ state.
BTwo intramolecular $O - H \cdot \cdot \cdot O$ hydrogen bonds link the two ligands.
CThe complex is paramagnetic with two unpaired electrons.
DNickel is tetrahedrally coordinated through the oxygen atoms.

Answer: A, B

Ni X^{2 +}

(

d^{8}

) with strong-field nitrogen donors forms a square planar, diamagnetic (

d s p^{2}

) complex in which each ligand binds through its two N atoms. The ligands are held together by two

O - H \cdot \cdot \cdot O

hydrogen bonds. So the statements about paramagnetism and tetrahedral O-coordination are wrong.