Which of the following complex has zero magnetic moment (spin only)?a)...
The potassium ferrocyanide, K4 [Fe(CN)6] due to strong ligand pairing of electrons occur and it has no unpaired electrons.
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Which of the following complex has zero magnetic moment (spin only)?a)...
Explanation:
Zero magnetic moment (spin only) means that all the electrons in the complex are paired and there is no unpaired electron to contribute to the magnetic moment. This can happen when the complex has a high spin state or a low spin state.
a) [Ni(NH3)6]CI2: Nickel(II) ion has 8 electrons in the d-orbital. In the presence of strong field ligands like NH3, the electrons pair up to form low spin complexes. So, the complex has a low spin state and zero magnetic moment.
b) Na3[FeF6]: Iron(III) ion has 5 unpaired electrons in the d-orbital. But in the presence of strong ligands like F-, the pairing energy is more than the energy required to pair up the electrons. So, the complex has a low spin state and zero magnetic moment.
c) [Cr(H2O)6]SO4: Chromium(III) ion has 3 unpaired electrons in the d-orbital. But in the presence of weak field ligands like H2O, the electrons don't pair up and form high spin complexes. So, the complex has a high spin state and a non-zero magnetic moment.
d) K4[Fe(CN)6]: Iron(II) ion has 4 unpaired electrons in the d-orbital. But in the presence of strong ligands like CN-, the pairing energy is more than the energy required to pair up the electrons. So, the complex has a low spin state and zero magnetic moment.
Therefore, option 'D' is the correct answer.