Question

The complex ion [Ni(CN)₄]²⁻ is ______.

Options

• square planar and diamagnetic

• tetrahedral and paramagnetic

• square planar and paramagnetic

• tetrahedral and diamagnetic

Answer 1

The complex ion [Ni(CN)₄]²⁻ is square planar and diamagnetic.

Explanation:

• Nickel in the +2 oxidation state (Ni²⁺) has a d⁸ electron configuration.
• CN⁻ is a strong field ligand, which causes Ni²⁺ to undergo pairing of electrons. This results in no unpaired electrons, meaning the complex is diamagnetic.
• The complex [Ni(CN)₄]²⁻ typically adopts a square planar geometry due to the strong ligand field and the d⁸ electron configuration.

Thus, the correct description for [Ni(CN)₄]²⁻ is square planar and diamagnetic.