Over the past two decades, we have witnessed a strong interest in developing Mg₃Sb₂ and related CaAl₂Si₂-type materials for low- and intermediate-temperature thermoelectric applications. In this review, we discuss how computations coupled with experiments provide insights for understanding chemical bonding, electronic transport, point defects, thermal transport, and transport anisotropy in these materials. Based on the underlying insights, we examine design strategies to guide the further optimization and development of thermoelectric Mg₃Sb₂-based materials and their analogs. We begin with a general introduction of the Zintl concept for understanding bonding and properties and then reveal the breakdown of this concept in AMg₂X₂ with a nearly isotropic three-dimensional chemical bonding network. For electronic transport, we start from a simple yet powerful atomic orbital scheme of tuning orbital degeneracy for optimizing p-type electrical properties, then discuss the complex Fermi surface aided by high valley degeneracy, carrier pocket anisotropy, and light conductivity effective mass responsible for the exceptional n-type transport properties, and finally address the defect-controlled carrier density in relation to the electronegativity and bonding character. Regarding thermal transport, we discuss the insight into the origin of the intrinsically low lattice thermal conductivity in Mg₃Sb₂. Furthermore, the anisotropies in electronic and thermal transport properties are discussed in relation to crystal orbitals and chemical bonding. Finally, some specific challenges and perspectives on how to make further developments are presented.

在过去的二十年中，我们见证了对开发用于中低温热电应用的Mg ₃ Sb ₂和相关的CaAl ₂ Si ₂型材料的强烈兴趣。在这篇综述中，我们讨论了计算与实验相结合如何为理解这些材料中的化学键，电子传输，点缺陷，热传输和传输各向异性提供了见识。基于潜在的见解，我们研究了设计策略以指导热电Mg ₃ Sb ₂的进一步优化和开发的材料及其类似物。我们首先介绍Zintl概念以了解键合和特性，然后在AMg ₂ X _2中揭示此概念的细分。具有几乎各向同性的三维化学键合网络。对于电子传输，我们从调整轨道简并性的简单而强大的原子轨道方案入手，以优化p型电性能，然后讨论高谷简并性，载流子各向异性和光导有效质量对复杂费米表面的影响。出色的n型传输特性，并最终解决了与电负性和键合特性有关的缺陷控制的载流子密度。关于热传输，我们讨论对Mg ₃ Sb _2中固有的低晶格热导率起源的见解。。此外，还讨论了与晶体轨道和化学键有关的电子和热传输性质的各向异性。最后，提出了一些关于如何取得进一步发展的具体挑战和观点。