The transition to the metallic state

Abstract An account is given of the theory that a crystalline or non-crystalline array of atoms will make a transition from the metallic to the non-metallic state as the interatomic distance is varied. Experimental evidence relevant to the theory is summarized. Wigner's (1938) suggestion that an electron gas might crystallize at sufficiently low densities is examined, and an experiment suggested by which it might be tested.