Coordination Chemistry and CFT

40 lessons, pages 2681–2720.

  1. Beyond Qualitative Crystal Field Theory — Why quantitative splitting, spin and isomer counting matter
  2. Electron Configurations of Transition Metal Ions — Removing 4s before 3d and assigning dⁿ counts in complexes
  3. The Barycentre Rule in Octahedral Fields — t2g at −0.4Δo and eg at +0.6Δo relative to the spherical field
  4. Defining Crystal Field Stabilisation Energy — Net energy lowering from occupying the split d orbitals
  5. Pairing Energy and Its Origins — Coulombic repulsion and loss of exchange energy on pairing
  6. Octahedral CFSE for d¹ to d³ Ions — Configurations with only one possible filling of t2g
  7. Octahedral CFSE for d⁴ to d⁷: High-Spin Cases — Weak-field filling and CFSE when Δo is less than P
  8. Octahedral CFSE for d⁴ to d⁷: Low-Spin Cases — Strong-field filling and including pairing-energy terms
  9. Octahedral CFSE for d⁸ to d¹⁰ Ions — Configurations where spin state no longer changes CFSE
  10. Predicting Spin State from Δo and P — Comparing numerical splitting and pairing energies
  11. Factors Affecting the Size of Δo — Metal oxidation state, period of the metal and ligand identity
  12. Tetrahedral Splitting and the 4/9 Relationship — Why Δt is roughly four-ninths of Δo for the same metal and ligand
  13. Calculating Tetrahedral CFSE — e at −0.6Δt and t2 at +0.4Δt and why tetrahedral complexes are high-spin
  14. Octahedral Site Preference Energy — Comparing octahedral and tetrahedral CFSE to explain site choice
  15. CFSE and Spinel Structures — Normal and inverse spinels such as Fe₃O₄ and Mn₃O₄
  16. CFSE and Hydration Enthalpies — The double-humped trend across the first transition series
  17. CFSE and Ionic Radii Trends — Irregular radii of M²⁺ ions explained by eg occupancy
  18. CFSE and Lattice Energies — Deviations from smooth trends in transition metal halides
  19. Jahn–Teller Distortion — Uneven eg occupancy, tetragonal elongation and Cu²⁺ complexes
  20. Square-Planar Complexes and d⁸ Ions — Large splitting, CFSE and why Ni²⁺, Pd²⁺ and Pt²⁺ adopt square planes
  21. CFSE and Kinetic Inertness — Labile and inert complexes and the special cases of d³ and low-spin d⁶
  22. Limitations of Crystal Field Theory — Covalency, the nephelauxetic effect and the move to ligand field theory
  23. Paramagnetism and Diamagnetism in Complexes — Unpaired electrons, attraction into a field and measurement ideas
  24. The Spin-Only Magnetic Moment Formula — μ = √(n(n+2)) BM and the Bohr magneton as a unit
  25. Calculating Spin-Only Moments — Tabulated values for one to five unpaired electrons
  26. Using Magnetic Moments to Assign Spin State — Distinguishing [Fe(H₂O)₆]²⁺ from [Fe(CN)₆]⁴⁻ by measured moment
  27. Working Backwards from Measured Moments — Deducing unpaired electrons, dⁿ count and oxidation state
  28. Orbital Contributions and Deviations from Spin-Only Values — Why Co²⁺ and some t2g configurations exceed spin-only predictions
  29. Spin Crossover Complexes — Temperature-driven switching between high-spin and low-spin states
  30. Magnetism, Colour and Spin State Together — Combining magnetic and spectroscopic evidence about Δ
  31. Systematic Isomer Counting: The Method — Fixing positions, using symmetry and eliminating duplicates
  32. Counting Isomers of MA₄B₂ and MA₃B₃ — Cis/trans and fac/mer isomers in octahedral complexes
  33. Counting Isomers of MA₂B₂C₂ — Five geometrical isomers and the chiral all-cis form
  34. Counting Isomers of Square-Planar MABCD — Three geometrical isomers and why none is optically active
  35. Isomers of Complexes with Bidentate Ligands — M(AA)₃, M(AA)₂B₂ and the Δ and Λ enantiomers
  36. Counting Stereoisomers Including Enantiomers — Totalling geometrical and optical isomers without double counting
  37. Symmetry Elements and Chirality in Complexes — Mirror planes, inversion centres and the quick chirality test
  38. Combining Structural and Stereoisomer Counts — Ionisation, linkage and stereoisomers in one complete count
  39. Integrated Problems: CFSE, Magnetism and Isomers — Multi-step exam problems linking structure, spin and energy
  40. Coordination Chemistry and CFT: Unit Review — Consolidating CFSE, spin-only moments and isomer counting