Question

A metal ion uses d²sp³ orbitals when forming a complex. What is its coordination number and the shape of the complex?

Short answer

The coordination number is 6 and the shape of the complex is octahedral.

Step-by-step solution

Valence bond theory will be used here

Valence bond theory explains to us that the ligand's orbital that is filled overlaps with the empty orbital of the metal ion; ligands donate their electron pairs, the metal ion accepts them and the coordination covalent bond is formed.

Coordination number and shape of the complex

When metal ion uses d2sp3 orbitals when forming a complex, it means that there are two 3d, one 4s, and three 4p orbitals mixed to form six d2sp3 hybrid orbitals. Thus, the coordination number of the metal ion would be 6 and the shape of the molecule is octahedral.