Labile and Inert Complexes
The kinetic classification of complexes according to how rapidly they exchange their ligands.
Unit
s⁻¹
In depth
Lability is a kinetic property entirely separate from thermodynamic stability: a complex can be thermodynamically unstable yet exchange ligands so slowly that it persists indefinitely. Inertness is typical of d³ and low spin d⁶ configurations, which have large crystal field stabilisation.
Examples in the real world
[Cr(H₂O)₆]³⁺ is inert with a half-life of days, while [Cu(H₂O)₆]²⁺ exchanges in nanoseconds.