Pace Kristen A, Klepov Vladislav V, Berseneva Anna A, Zur Loye Hans-Conrad
Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, SC, 29208, USA.
Chemistry. 2021 Apr 1;27(19):5835-5841. doi: 10.1002/chem.202004632. Epub 2021 Jan 31.
Covalency in actinides has emerged as a resounding research topic on account of the technological importance in separating minor actinides from lanthanides for spent nuclear fuel processing, and utilization of their distinct bonding properties has been realized as a route towards overcoming this challenge. Because of the limited radial extent of the 4f orbitals, there is almost no 4f electron participation in bonding in lanthanides; this is not the case for the actinides, which have extended 5f orbitals that are capable of overlapping with ligand orbitals, although not to the degree of overlap as in the d orbitals of transition metals. In this concept paper, a general description of covalency in actinide compounds is provided. After introducing two main approaches to enhance covalency, either by exploiting increased orbital overlap or decreasing energy differences between the orbitals causing orbital energy degeneracy, the current state of the field is illustrated by using several examples from the recent literature. This paper is concluded by proposing the use of actinide chalcogenides as a convenient auxiliary tool to study covalency in actinide compounds.
由于在乏核燃料处理中从镧系元素中分离次要锕系元素具有重要的技术意义，锕系元素中的共价性已成为一个备受关注的研究课题，并且利用它们独特的键合性质已被视为克服这一挑战的途径。由于4f轨道的径向范围有限，镧系元素中几乎没有4f电子参与键合；而锕系元素则不同，它们具有扩展的5f轨道，能够与配体轨道重叠，尽管重叠程度不如过渡金属的d轨道。在这篇概念论文中，对锕系化合物中的共价性进行了一般性描述。在介绍了两种增强共价性的主要方法后，即通过利用增加轨道重叠或减小导致轨道能量简并的轨道之间的能量差，通过引用近期文献中的几个例子来说明该领域的现状。本文最后提出使用锕系硫族化合物作为研究锕系化合物中共价性的便捷辅助工具。
