Crystal structures of the alpha''-cerium phases.

Endo et al. [Endo, S., Sasaki, H. & Mitsui, T. (1972) J. Phys. Soc. Jpn. 42, 882-885] have reported x-ray diffraction data for an unidentified phase of cerium metal observed in the 50- to 100-kbar range. It is shown that the unknown phase is a variant of the metastable monoclinic phase, alpha''-Ce, previously observed. The complete structure of the new form of alpha''-Ce is deduced.

Superconductivity: the transition temperature peak below four electrons per atom.

It is shown that the superconducting transition temperature for compounds in seven different structure types exhibits a peak at about 3.7 to 3.9 valence electrons per atom.

Superconductivity of alpha-uranium and the role of 5f electrons.

A much sharper and lower superconducting transition has been found for alpha-uranium than any reported previously. A model that explains the unusual volume dependence of alpha-uranium below 43 degrees K and the unusual pressure dependence of its superconducting transition temperature is presented.