Crystal Field Theory — d-Orbital Splitting
Split the d-orbitals with a ligand field and watch spin, magnetism and colour follow.
About this simulation
Crystal field splitting made interactive. Students choose octahedral or tetrahedral geometry, a ligand from the spectrochemical series (I⁻ → CN⁻, which sets the field strength Δ) and the d-electron count, and the energy-level diagram fills the t₂g/eₒ (or e/t₂) sets by the Hund/pairing rules. A strong field (Δ > pairing energy P) forces low-spin, a weak field stays high-spin, and tetrahedral Δt = 4/9 Δo is always high-spin. The number of unpaired electrons, para/diamagnetism, CFSE and even the observed colour (complementary to the absorbed d-d wavelength, λ ≈ 1240/Δ) update live — so [Fe(H₂O)₆]²⁺ (high-spin, paramagnetic) versus [Fe(CN)₆]⁴⁻ (low-spin, diamagnetic) becomes something students build rather than memorise.