In contrast to its next-door neighbors the group 11 elements, the element palladium in organic chemistry does not involve preparation of<unk>  compounds itself but rather<unk>  reactive intermediates . On top of that in many reactions only catalytical amounts of the metal are used.
Palladium reacts with alkenes to form a pi complex which can react with a multitude of nucleophiles akin a oxymercuration reaction. The C-Pd bond is then removed by a reduction or an elimination.  In the industrially important Wacker process, ethylene is converted to acetaldehyde with palladium chloride.
Allyl compunds with suitable leaving groups react with palladium(II) salts to pi-allyl complexes having hapticity 3 such as the Allylpalladium chloride dimer. These intermediates too react with nucleophiles for example carbanions derived from malonates 
Allylpalladium intermediates also feature in the Trost asymmetric allylic alkylation and the Carroll rearrangement and an oxo variation in the Saegusa oxidation.
Zerovalent Pd(0) compounds such as tris(dibenzylideneacetone)dipalladium(0) and tetrakis(triphenylphosphine)palladium(0) react with halocarbon R-X in oxidative addition to R-Pd-X intermediates with covalent Pd-C bonds. This chemistry forms the basis of a large class of organic reactions called coupling reactions. Palladium(II) trifluoroacetate has been demonstrated to be effective in aromatic decarboxylation :
In the proposed reaction mechanism Pd(II) replaces the carboxylic acid proton while losing a TFA group, carbon dioxide is lost in a first order reaction and TFA destroys the formed Ar-Pd-TFA complex without Pd changing its oxidation state.
Organopalladium
Chromium carbide
Psyllium
Cilium
Tantalum carbide
Vinyl chloride
Organonickel
Cadmium sulfide