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The correct order of magnetic moments (spin only values in B.M.) among the following is

1. [Fe(CN)6]4− > [MnCl4]2− > [CoCl4]2−
2. [MnCl4]2− > [Fe(CN)6]4− > [CoCl4]2−
3. [MnCl4]2− > [CoCl4]2− > [Fe(CN)6]4−
4. [Fe(CN)6]4− > [CoCl4]2− > [MnCl4]2−

Correct answer: [MnCl4]2− > [CoCl4]2− > [Fe(CN)6]4−

Solution

The correct order reflects the number of unpaired electrons in each complex, with [MnCl4]2− having the highest spin state due to its d5 configuration, followed by [CoCl4]2− with d7 and unpaired electrons, and [Fe(CN)6]4− being low-spin d6 with no unpaired electrons.

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