Question

Spin free complex?

• A. \( \text{Fe}^{3+} \)
• B. \( \text{Co}^{2+} \)
• C. \( \text{Ni}^{2+} \)
• D. \( \text{Cu}^{2+} \)

Hint:

To determine if a complex is spin-free, check for paired electrons. Spin-free complexes typically occur in ions with fully paired d-electrons.

Answer 1

The Correct Option is D

A spin-free complex refers to a complex where all electrons are paired, resulting in no unpaired electrons and no magnetic behavior. Among the given metal ions, Cu\(^{2+}\) has a 3d\(^{9}\) electron configuration in its high-spin state, which can be arranged in a way that results in no unpaired electrons in its complex, making it spin-free. Thus, the correct answer is Cu\(^{2+}\).