Instead of using sulfated molecules or the fairly big Buckminster fullerenes recently it became possible to synthesize crystals from the hydrocarbon picene and phenanthrene. Doping the crystal picene and phenanthrene with alkali metals such as potassium or rubidium and annealing for several days leads to superconductivity with transition temperatures up to . For AxPhenanthrene, the superconductivity is possible unconventional. Both phenanthrene and picene are called phenanthrene-edge-type polycyclic aromatic hydrocarbon. The increasing number of benzene rings results in higher T.