Hemilability and nonrigidity in a series of mixed
P,
P
S donor ligands has been studied in the complexes [Pd(
P,
P
S)Cl
2], [Pd(η
3-C
3H
5)(
P,
P
S)][SbF
6], and [Rh(cod)(
P,
P
S)][SbF
6] (
P,
P
S = Ph
2P-Q-P(S)Ph
2). The effect of bite angle, the rigidity of the ligand backbone, and the role of the ancillary ligands are discussed.