The periodic bulk structures of metal–organic frameworks (MOFs) can be solved by diffraction-based techniques; however, their non-periodic local structures—such as crystal surfaces, grain boundaries, defects, and guest molecules—have long been elusive due to a lack of suitable characterization tools. Recent advances in (scanning) transmission electron microscopy ((S)TEM) has made it possible to probe the local structures of MOFs at atomic resolution. In this article, we discuss why high-resolution (S)TEM of MOFs is challenging and how the new low-dose techniques overcome this challenge, and we review various MOF structural features observed by (S)TEM and important insights gained from these observations. Our discussions focus on real-space imaging, excluding other TEM-related characterization techniques (e.g. electron diffraction and spectroscopy).

金属有机框架 (MOF) 的周期性整体结构可以通过基于衍射的技术来解决；然而，由于缺乏合适的表征工具，它们的非周期性局部结构——如晶体表面、晶界、缺陷和客体分子——长期以来一直难以捉摸。（扫描）透射电子显微镜 ((S)TEM) 的最新进展使得以原子分辨率探测 MOF 的局部结构成为可能。在这篇文章中，我们讨论了为什么 MOF 的高分辨率 (S)TEM 具有挑战性以及新的低剂量技术如何克服这一挑战，我们回顾了 (S)TEM 观察到的各种 MOF 结构特征以及从这些观察中获得的重要见解. 我们的讨论集中在实空间成像上，不包括其他与 TEM 相关的表征技术（例如电子衍射和光谱学）。