木炭和金刚石都是炭的同素异形物Charcoal and diamond are allotropes of carbon.把元素中的多晶现象称为同素异构性.Polymorphism in elements is called allotropy.纯钛以两种同素异形的形式存在.Titanium in the pure state can exist in either of two allotropic forms....

“同素”的英语可以翻译为：homoatomic ...