Quick Recap — VBT, CFT & Magnetism

  • Spin-only moment: μ=n(n+2)\mu=\sqrt{n(n+2)} BM (n=n= unpaired electrons): n=1→1.73n=1\to1.73, 2→2.832\to2.83, 3→3.873\to3.87, 4→4.904\to4.90, 5→5.925\to5.92.
  • Octahedral hybridisation: inner (low spin) d2sp3d^2sp^3; outer (high spin) sp3d2sp^3d^2. Tetrahedral =sp3=sp^3; square planar =dsp2=dsp^2.
  • CFT: octahedral field splits d into lower t2gt_{2g} and higher ege_g; strong field ⇒\Rightarrow pairing (low spin).
  • Spectrochemical series (increasing field): I−<Br−<Cl−<F−<H2O<NH3<en<CN−≈COI^-<Br^-<Cl^-<F^-<H_2O<NH_3<en<CN^-\approx CO.