超原子是一个表现出元素的原子性质的原子团簇。钠原子从蒸汽冷却时自然凝结成团簇时优先含有原子个数为(2,8,20,40,58等)的幻數(英语:Magic number (chemistry))。前两个可以被看作是需要分别填充的第一和第二壳的电子数目。超原子中的自由电子占据整个的原子团外层,而不是分散在单个的原子上。价电子光谱性质及团簇作为整体所具有的化学价态要与相应的原子相似。根据超原子特殊的物理化学特性及潜在的应用价值,有人提出了三维元素周期表的概念[1]。比如TiO、ZrO和WC分别是金属Ni、Pd和Pt的“超级原子”。
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