Department of Chemistry and Research Institute for Basic Sciences, Kyung Hee University, Seoul 02447, Korea.
Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.
Molecules. 2021 Jan 20;26(3):531. doi: 10.3390/molecules26030531.
In this review on spin exchanges, written to provide guidelines useful for finding the spin lattice relevant for any given magnetic solid, we discuss how the values of spin exchanges in transition metal magnetic compounds are quantitatively determined from electronic structure calculations, which electronic factors control whether a spin exchange is antiferromagnetic or ferromagnetic, and how these factors are related to the geometrical parameters of the spin exchange path. In an extended solid containing transition metal magnetic ions, each metal ion M is surrounded with main-group ligands L to form an ML polyhedron (typically, n = 3-6), and the unpaired spins of M are represented by the singly-occupied d-states (i.e., the magnetic orbitals) of ML. Each magnetic orbital has the metal d-orbital combined out-of-phase with the ligand p-orbitals; therefore, the spin exchanges between adjacent metal ions M lead not only to the M-L-M-type exchanges, but also to the M-L…L-M-type exchanges in which the two metal ions do not share a common ligand. The latter can be further modified by d cations A such as V and W to bridge the L…L contact generating M-L…A…L-M-type exchanges. We describe several qualitative rules for predicting whether the M-L…L-M and M-L…A…L-M-type exchanges are antiferromagnetic or ferromagnetic by analyzing how the ligand p-orbitals in their magnetic orbitals (the ligand p-orbital tails, for short) are arranged in the exchange paths. Finally, we illustrate how these rules work by analyzing the crystal structures and magnetic properties of four cuprates of current interest: -CuVO, LiCuVO, (CuCl)LaNbO, and Cu(CO)(OH).
在这篇关于自旋交换的综述中，我们旨在为寻找任何给定磁性固体相关的自旋晶格提供有用的指导，讨论如何从电子结构计算中定量确定过渡金属磁性化合物中的自旋交换值，哪些电子因素控制自旋交换是反铁磁性还是铁磁性，以及这些因素如何与自旋交换路径的几何参数相关。在一个包含过渡金属磁性离子的扩展固体中，每个金属离子 M 都被主族配体 L 包围，形成一个 ML 多面体（通常为 n = 3-6），并且 M 的未配对自旋由 ML 的单占据 d 态（即，磁性轨道）表示。每个磁性轨道都具有与配体 p 轨道反相组合的金属 d 轨道；因此，相邻金属离子 M 之间的自旋交换不仅导致 M-L-M 型交换，而且还导致 M-L…L-M 型交换，其中两个金属离子不共享共同的配体。后者可以通过 V 和 W 等 d 阳离子进一步修饰，以桥接 L…L 接触，生成 M-L…A…L-M 型交换。我们通过分析它们的磁性轨道中的配体 p 轨道（简称配体 p 轨道尾部）在交换路径中的排列方式，描述了几种定性规则，用于预测 M-L…L-M 和 M-L…A…L-M 型交换是反铁磁性还是铁磁性。最后，我们通过分析四种当前感兴趣的铜酸盐的晶体结构和磁性性质来举例说明这些规则的工作原理：-CuVO、LiCuVO、(CuCl)LaNbO 和 Cu(CO)(OH)。
