Allylpalladium(II) chloride dimer (APC) is a chemical compound with the formula [(η3-C3H5)PdCl]2.

This yellow air-stable compound is an important catalyst used in organic synthesis.

Each allyl group lies in a plane at an angle of about 111.5° to the square formed by the palladium and carbon atoms, and the Pd–C distances are all equal.

[2] Another method is the reaction of propene with palladium(II) trifluoroacetate, followed by ion exchange with chloride:[3] APC reacts with sources of cyclopentadienyl anion to give the corresponding 18e− complex cyclopentadienyl allyl palladium: The dimer reacts with a variety of Lewis bases (:B) to form adducts (η3-C3H5)PdCl:B.

APC catalyzes many organic reactions, such as cross-coupling, nucleophilic addition to dienes, and decomposition of diazo compounds to reactive carbenes.