Crystal Field Stabilization Energy Calculator

CFSE Calculator

Geometry: Octahedral Tetrahedral Square Planar Trigonal Bipyramidal d-electron count (dⁿ): d⁰ d¹ d² d³ d⁴ d⁵ d⁶ d⁷ d⁸ d⁹ d¹⁰ Spin state (only for octahedral d⁴–d⁷): High Spin Low Spin Include pairing energy? Pairing energy P (in units of Δ, optional):

Notes:

• Tetrahedral and trigonal bipyramidal complexes are typically high spin.
• Square planar complexes are typically low spin (large Δ).
• Trigonal bipyramidal uses standard splitting energies relative to Δ_tbp (≈ Δ₀).
• Pairing energy is approximate (extra pairs relative to high-spin spherical field).

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CFSE Reference Table (in Δ units, excluding pairing energy P)

dn	Octahedral High Spin	Octahedral Low Spin	Tetrahedral (High Spin)	Square Planar (Low Spin)	Trigonal Bipyramidal (High Spin)
d⁰	0	0	0	0	0
d¹	-0.400	-0.400	-0.600	-0.456	-0.164
d²	-0.800	-0.800	-1.200	-0.912	-0.328
d³	-1.200	-1.200	-0.800	-1.368	-1.144
d⁴	-0.600	-1.600	-0.400	-1.824	-0.872
d⁵	0	-2.000	0	-2.280	-1.688
d⁶	-0.400	-2.400	-0.600	-2.736	-1.416
d⁷	-0.800	-1.800	-1.200	-2.092	-2.232
d⁸	-1.200	-1.200	-0.800	-2.548	-1.960
d⁹	-0.600	-0.600	-0.400	-1.904	-1.688
d¹⁰	0	0	0	-1.360	-2.036

Square planar values approximate Δ_sp ≈ 1.23 Δ₀. Trigonal bipyramidal values use standard relative energies (in units of Δ_tbp).