Crystal Field Splitting Energy Quiz

Crystal Field Splitting Energy (CFSE)

• Crystal field splitting energy (CFSE) is calculated differently for octahedral and tetrahedral complexes.

Octahedral Complexes

• For octahedral coordination (6 total ligands), CFSE is given by the formula: eg x 0.6 + bg x 0.4.
• In terms of electron pairing: eg reflects the higher energy orbitals while bg reflects lower energy orbitals.
• Example calculation of CFSE yields: ΔT = 3 x 0.4 - 4 x 0.6 = -1.2.

Tetrahedral Complexes

• For tetrahedral coordination (4 total ligands), CFSE is also calculated with the same formula: eg x 0.6 + bg x 0.4.
• Calculation for a tetrahedral complex shows: eg = 0 x 0.6 + 6 x 0.4 = 2.4.

Diagrams

• Represents octahedral and tetrahedral geometries visually.
  • "Co(H2O)4) 42 (tetrahedral)": propeller diagram.
  • Tetrahedral complex shown as a flower with 4 petals.
  • Octahedral complex depicted as a flower with 6 petals.

Element Configurations

• Iron (Fe) has electronic configuration of 4s3d6.
• Iron (Fe²⁺) retains the 4s3d6 configuration as a cation.
• Cobalt (Co) has electronic configuration of 4s3d7.
• Cobalt (Co²⁺) similarly has the 4s3d7 configuration as a cation.

Cases

• Case A=0: Indicates all electrons are unpaired with an overall configuration of 11 11 11 11, resulting in +0.6 for eg and -0.4 for bg; maintains the appearance of 11 11 11 11.
• Case A > 0: Reflects a differently unpaired arrangement of electrons, shown by the configuration 1 1 1 1 1 1 7 7, with the same energy contributions of +0.6 for eg and -0.4 for bg.