Question

Select the correct statements for [Fe(CN)\(_6\)]\(^{3-}\) complex:
(A) Paramagnetic
(B) sp\(^3\)d\(^2\) hybridization
(C) Magnetic moment = 5.92 BM
(D) d\(^2\)sp\(^3\) hybridization

• A. (A) and (D) only
• B. (A), (B) and (C) only
• C. (B), (C) and (D) only
• D. (B), (C) and (D) only

Hint:

In coordination complexes, the type of hybridization and magnetic moment depend on the nature of the ligands. Strong field ligands like cyanide lead to low-spin complexes and d\(^2\)sp\(^3\) hybridization.

Answer 1

The Correct Option is C

For the complex \([Fe(CN)_6]^{3-}\), let's evaluate each statement:
Step 1: Paramagnetism (A)
The iron ion in \([Fe(CN)_6]^{3-}\) is in the +3 oxidation state, with Fe\(^{3+}\) having an electron configuration of \( [Ar] \, 3d^5 \). The presence of unpaired electrons indicates paramagnetism. However, further analysis of hybridization and magnetic moment is required for the final determination.
Step 2: Hybridization (B) and (D)
Cyanide (CN\(^-\)) acts as a strong field ligand in this complex, leading to significant splitting of the d-orbitals. This results in iron undergoing d\(^2\)sp\(^3\) hybridization, forming a stable low-spin complex. Note that the statement (B) mentions sp\(^3\)d\(^2\) hybridization which is incorrect for a low-spin octahedral complex.
Step 3: Magnetic Moment (C)
The magnetic moment is reported as 5.92 BM. This value aligns with a low-spin octahedral complex featuring a d\(^5\) electron configuration. The magnetic moment is calculated using the formula: \[\mu = \sqrt{n(n+2)}\] where \(n = 5\) for a d\(^5\) configuration, yielding 5.92 BM. Conclusion:
The correct statements are:
- (C) Magnetic moment = 5.92 BM
- (D) d\(^2\)sp\(^3\) hybridization
Thus, the correct answer is:
(3) (C) and (D) only.
Final Answer: \[\boxed{\text{The correct answer is (C) and (D) only.}}\]