Electron crystallography

Electron crystallography is a method to determine the arrangement of atoms in solids using an electron microscope. It can complement X-rays cannot, because electrons interact more strongly with atoms than X-rays do. Thus, X-rays will travel through a thin 2-dimensional crystal without diffracting significantly, whereas electrons can be used to form an image. Conversely, the strong interaction between electrons and proteins makes thick (e.g. 3-dimensional) crystals impervious to electrons, which only penetrate short distances.