Identify the diamagnetic octahedral complex ions from below ; A. [Mn(CN)6]3- B. [Co(NH3)6]3+ C. [Fe(CN)6]4- D. [Co(H2O)3F3] Choose the correct answer from the options given below:

The correct answer is Option 1. Full mathematical solution steps and hints are accessible in the interactive StemCET workspace.

Chemistry Q62 – JEE-MAIN 2025

← Back

Home Chemistry Coordination CompoundsQuestion #345

Identify the diamagnetic octahedral complex ions from below ; A.

[M n (C N)_{6}]^{3 -}

[C o (N H_{3})_{6}]^{3 +}

[F e (C N)_{6}]^{4 -}

[C o (H_{2} O)_{3} F_{3}]

Choose the correct answer from the options given below:

Clue 1 of 3: Magnetic Properties

Diamagnetic substances are those that have no unpaired electrons, meaning all electrons are paired.

🧠 Full Solution Path

Step 1: Determine Oxidation State and d-electron Configuration✦ Active

For each complex, calculate the oxidation state of the central metal ion and determine its d-electron configuration:

\begin{array}{ll} A. [M n (C N)_{6}]^{3 -} & M n^{3 +} (d^{4}) \\ B. [C o (N H_{3})_{6}]^{3 +} & C o^{3 +} (d^{6}) \\ C. [F e (C N)_{6}]^{4 -} & F e^{2 +} (d^{6}) \\ D. [C o (H_{2} O)_{3} F_{3}] & C o^{3 +} (d^{6}) \end{array}

Step 2: Analyze Ligand Field Strength and Electron Pairing○ Expand

Identify the ligand field strength (strong field ligand, SFL, or weak field ligand, WFL) and determine the number of unpaired electrons for each octahedral complex:

\begin{array}{ll} A. [M n (C N)_{6}]^{3 -} & C N^{-} (SFL) . d^{4} (low spin, t_{2 g}^{4} e_{g}^{0}) . Unpaired electrons = 2. (Paramagnetic) \\ B. [C o (N H_{3})_{6}]^{3 +} & N H_{3} (SFL) . d^{6} (low spin, t_{2 g}^{6} e_{g}^{0}) . Unpaired electrons = 0. (Diamagnetic) \\ C. [F e (C N)_{6}]^{4 -} & C N^{-} (SFL) . d^{6} (low spin, t_{2 g}^{6} e_{g}^{0}) . Unpaired electrons = 0. (Diamagnetic) \\ D. [C o (H_{2} O)_{3} F_{3}] & H_{2} O, F^{-} (WFL) . d^{6} (high spin, t_{2 g}^{4} e_{g}^{2}) . Unpaired electrons = 4. (Paramagnetic) \end{array}

💡 Teacher's Secret Hint

Remember that $C N^{-}$ and $N H_{3}$ are strong field ligands, while $H_{2} O$ and $F^{-}$ are weak field ligands.

Step 3: Identify Diamagnetic Complexes○ Expand

Diamagnetic complexes are those with zero unpaired electrons. Based on the analysis, complexes B and C are diamagnetic.

✦ STEM Console utilizes AI models to generate step-by-step explanations and math clues. AI can make mistakes.

Chemistry Question 62 – JEE-MAIN 2025

Clue 1 of 3: Magnetic Properties

🧠 Full Solution Path