Gas-phase ion mobility measurements have been used to study the structures and isomerization of PdCn+ (n 10-60) clusters. Non-fullerene isomers of PdCn+ clusters are similar to those of C-n(+) and MC(n)(+) (M = La and Nb) clusters, and include metal-containing mono- and bicyclic rings and graphite sheets. Neither endohedral nor nonendohedral PdCn+ fullerene isomers are detected. When collisionally heated, PdCn+ clusters efficiently convert into fullerenes, but the exothermicity of this process results in the loss of the Pd atom and the formation of a pure carbon cluster cation. PdCn+ bicyclic rings with an odd number of carbon atoms efficiently isomerize into monocyclic rings, while no evidence is found for this isomerization process for bicyclic rings with an even number of carbon atoms.