12 June 2019 - Tim Gruene (Vienna University, AT)

An EIGER X 1M detector turns a Transmission Electron Microscope into an Electron Diffractometer


Last year, electron crystallography attracted much attention when the method ranked fifth for the public vote of the Science Breakthrough 2018. This attention results from a diverse number of publications, where electron diffraction was used to solve structures of that are relevant in various fields of chemistry. For example, very complex structures of MOFs [1], zeolites [2], and organic structures can be solved with electron crystallography where X-ray failed from too small crystals.

In this talk I will present how we combined an EIGER hybrid pixel detector and a transmission electron microscope in order to create an electron diffractometer.

I will discuss how to determine the parameters required for data processing and present example structures that were solved with this setup. The results demonstrate that such a setup is suitable to complement any X-ray facility for routine structure determination.[3]

I will also present a solution to the missing wedge problem in electron diffraction. Conventional sample supports leads to systematically incomplete data. In cases of low symmetry space groups, this can seriously compromise the structure quality. Our grids offer simple solutions to this problem and enable complete structure by merging data from a small number of crystals. These grids are also suitable for automated data collection [4]. Such a combination is of large interest e.g. for the screening of polymorphs.

[1] Wang et al., Chem Eur. J. (2018), 24, 17429-17433

[2] Simancas et al, JACS (2016), 138, 10116–10119

[3] Gruene et al., Angew. Chemie Int. Ed. (2018), 57, 16313-16317

[4] Cichocka et al., J. Appl. Cryst. (2018), 1652-1661