Question

The geometry and magnetic behaviour of the complex $[Ni(CO)_4]$ are

• A. tetrahedral geometry and paramagnetic
• B. square planar geometry and diamagnetic
• C. square planar geometry and paramagnetic
• D. tetrahedral geometry and diamagnetic

Answer 1

The Correct Option is D

The question asks about the geometry and magnetic behavior of the complex [Ni(CO)_4]. To solve this, we need to analyze the electronic configuration and the type of ligands involved.

1. Electronic Configuration of Nickel:
   • Nickel in its atomic form has the electronic configuration [Ar] 3d^8 4s^2.
   • In [Ni(CO)_4], nickel is in the zero oxidation state, so its configuration remains the same 3d^8 4s^2.
2. Nature of Carbonyl Ligands:
   • CO is a strong field ligand and causes pairing of the electrons in the d orbitals.
   • This leads to the following electronic configuration: 3d^{10} 4s^0 4p^0.
3. Hybridization and Geometry:
   • With the electronic configuration becoming 3d^{10}, all electrons are paired.
   • The hybridization involved in forming the complex is sp^3, leading to a tetrahedral geometry.
4. Magnetic Behavior:
   • Since all electrons in [Ni(CO)_4] are paired, there are no unpaired electrons.
   • This results in the complex being diamagnetic.

Thus, the correct answer is that [Ni(CO)_4] has tetrahedral geometry and is diamagnetic.