a bivalent and trivalent metallic element of the rare earth group
例句
用作名词 (n.)
The lighter rare-earth metals, from cerium to europium in the first half of the series, have more complex crystal structures than the heavier elements. 轻的稀土金属，从铈到铕的前一半序列比重元素具有更为复杂的晶体结构。
美
[jʊr'oʊpiəm]
