摘要
The phenomenon of the appearance of unusual steep double peaks (or double deep valleys) at Eu anl Yb of a series of physical and chemical properties of lanthanide metals, has been called 'double peak effect' and is generally explained from Eu and Yb, both of which are 2-valence metals and have larger metallic radius in comparison with the neighbouring 3-valence rare earths. From the fine electronic structures of the lanthanide metals the authors have calculated a series of their quantitative physical properties,