摘要：

The physical properties of the "actinide" elements, in the seventh row of the periodic table, are reviewed with emphasis on the occurrence of superconductivity and magnetism in Ac through Cm. The properties of these elements are compared with those of the transition metals and the rare earths, both of which groups are resembled to some extent by the actinides. The superconductors among the actinides are Th, Pa, and U, although the latter (and possibly Pa also) is superconducting in its room temperature phase only under pressure. The several peculiar superconducting properties of U, especially the positive isotope effect exhibited by α-U under pressure, are discussed. Recent theoretical explanations of the positive isotope effect are considered, and it is suggested that hyperfine interactions may play a role in the superconductivity of this metal. An empirical rule is used to predict the isotope effects in Th and cubic Pa, and the prospects for superconductivity in Ac, Np, Pu, and Am are also discussed.

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