The structures of small mixed iron carbon cluster anions, Fe(n)C(m)- (n = 1, 2, 3 and m = 2-8) have been studied using gas phase ion chromatography. In the one iron atom case, results show a competition between linear structures and two-dimensional (planar) clusters. The two iron atom clusters, on the other hand, are pure monocyclic rings with the two iron atoms nearest neighbors. The three iron species are three-dimensional, and several possible structures are evaluated. In all cases the carbon atoms maintain a continuous chain and no carbon dimers are observed that would be characteristic of MetCar precursors.