Prior to their identification as a series of f-elements, the actinides were thought to be a fourth row of the transition metal series, principally because the oxidation states of the early actinide elements were similar to those encountered in their transition metal homologues. The rich redox chemistry observed in the actinides is in contrast to the predominantly trivalent oxidation states encountered in the lanthanide series. Unlike the lanthanides and transition metals, the chemistry of the early actinide elements is governed by the interplay of both the 5f and 6d electrons. The relative energies of the electrons and orbitals changes as Z is increased causing a periodic stabilization of the 5f orbitals relative to the 6d resulting in different chemistries being observed for these elements, influencing molecular structure and oxidation reduction properties. In moving from Th, to Pa, to U, the chemistry and bonding transitions from that of considerable d-character at Th to predominantly f-character at U. Protactinium is at the chemical intersection of this phenomenon, and studying its chemistry is critical to understanding the roles of both the 5f and 6d electrons in the chemistiy of the actinide elements.
展开▼
机译：在其作为一系列F元素的识别之前，散曲线被认为是过渡金属系列的第四行，主要是因为早期的致动元件的氧化状态与其过渡金属同源物中遇到的那些相似。在散曲线中观察到的富含氧化还原化学与镧系元素系列中遇到的主要三价氧化态相反。与镧系元素和过渡金属不同，早期致动元素的化学由5F和6D电子的相互作用控制。作为Z的电子和轨道变化的相对能量增加，导致5F轨道相对于6D的周期性稳定，导致这些元素观察到不同的化学物质，影响分子结构和氧化还原性能。在从TH移动到Pa，对U中的化学和粘合转变，在U. prot actinium在U. prot actinium at th Th主要的D-regy的转变为这一现象的化学交叉点，并研究其化学是至关重要的理解5F和6D电子在散瞳元件的展示中的作用。
展开▼
