Statement I: In octahedral complexes, the three t2g orbitals are stable and of low energy while the two eg-orbitals are unstable and have high energy
Statement II: In octahedral complexes, the three t2g orbitals experience less repulsion from the ligands while two eg orbitals experience more repulsion from the ligands due to their orientation
Answer & explanation
Correct answer: option 1
The correct option is: 1. Both Statement I and Statement II are correct, and Statement II is the correct explanation of Statement I.
Statement I: In octahedral complexes, the three \(t_{2g}\) orbitals are stable and of low energy, while the two \(e_g\) orbitals are unstable and have high energy.
Statement II: In octahedral complexes, the three \(t_{2g}\) orbitals experience less repulsion from the ligands, while the two \(e_g\) orbitals experience more repulsion from the ligands due to their orientation.
Both statements are correct:
Statement I is true. In an octahedral complex, the \(t_{2g}\) orbitals are lower in energy and are stabilized due to strong ligand field splitting. This splitting results from the arrangement of ligands in an octahedral geometry, which creates a large energy gap between the \(t_{2g}\) and \(e_g\) sets of orbitals. The \(e_g\) orbitals, on the other hand, are destabilized and higher in energy due to the increased repulsion from the ligands.
Statement II is also true. The orientation of the \(t_{2g}\) and \(e_g\) orbitals in an octahedral complex influences their interaction with the ligands. The \(t_{2g}\) orbitals point in-between the ligands and experience less repulsion, resulting in lower energy and greater stability. In contrast, the \(e_g\) orbitals point directly at the ligands and experience more repulsion, leading to higher energy and reduced stability.
Statement II provides the correct explanation for why the \(t_{2g}\) orbitals are stable and of low energy, while the \(e_g\) orbitals are unstable and have high energy in octahedral complexes.