Which of the following statements is true about the complex [Fe(CN)6]3-?

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Q: Which of the following statements is true about the complex [Fe(CN)6]3-?

Solution: [Fe(CN)6]3- is diamagnetic because all the electrons are paired in the d-orbitals of Fe in the +3 oxidation state.

Steps: 6

Step 1: Identify the complex ion [Fe(CN)6]3-. This means it has one iron (Fe) atom and six cyanide (CN) ligands.
Step 2: Determine the oxidation state of iron in this complex. Since the overall charge is -3 and each CN has a charge of -1, the oxidation state of Fe must be +3.
Step 3: Write the electron configuration for Fe in the +3 oxidation state. Iron (Fe) has an atomic number of 26, so its electron configuration is [Ar] 4s2 3d6. For Fe3+, we remove 3 electrons, resulting in [Ar] 3d5.
Step 4: Analyze the d-orbitals. In the +3 state, Fe has 5 electrons in the 3d orbitals. These electrons can be arranged in the d-orbitals.
Step 5: Determine if the electrons are paired or unpaired. In a strong field ligand environment like CN-, the electrons will pair up in the lower energy d-orbitals, resulting in all electrons being paired.
Step 6: Conclude that since all the electrons in the d-orbitals are paired, the complex [Fe(CN)6]3- is diamagnetic.