How does crystal field stabilization energy influence stereochemistry?

CFSE and Stereochemistry – Simple Explanation

1. What is CFSE?

• When ligands surround a metal, the metal’s d-electrons go into orbitals of different energies.
• The energy saved by filling lower-energy orbitals is called Crystal Field Stabilization Energy (CFSE).

2. How it affects geometry

• The metal chooses the shape that gives the most CFSE, because it is more stable.
• Example:
  • d³ or low-spin d⁶ → octahedral preferred.
  • d⁸ metals (Ni²⁺, Pd²⁺, Pt²⁺) → square planar preferred.

3. How it affects stereochemistry

• CFSE influences:
  • The overall shape of the complex (octahedral, tetrahedral, square planar).
  • The arrangement of ligands (cis/trans, fac/mer).
  • Distortions in geometry to get extra stability (like Jahn–Teller effect).

In short:
The geometry and 3D arrangement of a metal complex are chosen to maximize CFSE, which determines its stereochemistry.