Other ferrocene or ferrocenium compounds may include (R.sub.5-xC.sub.5H.sub.x)Fe(R'.sub.5-yC.sub.5H.sub.y) where any R and R' is independently methyl, ethyl, propyl, butyl, penta or other alkyl group and x and y are independently 0, 1, 2, 3, 4 or 5 for