We present a detailed structure analysis of zeolite IM-18 with a complex disordered framework structure that was unknown for more than 10 years.^[1,2] IM-18 has a novel framework topology and a three-dimensional 8x8x10-ring channel system, making it ideal for the shape selective catalysis of small molecules. The unique disorder in the structure makes the structure analysis complicated, so we combined three complementary techniques, including single-crystal electron diffraction (SCED), high resolution transmission electron microscopy (HRTEM) and synchrotron X-ray powder diffraction (XRPD) to reveal the details of the disorder.
 
Solving the structure of a polycrystalline material that is also disordered can be very challenging as there are no standard procedures to follow. Rotation electron diffraction (RED) allowed us to solve the average structure of the material, the local ordering was observed from the HRTEM images (Fig. 1B-E), but the fine details of the structure and location of the OSDA and Ge could only be derived from XRPD data (Fig. 1A). We found that IM-18 contains two different types of stacking faults along two directions, which were difficult to observe using HRTEM because of the beam sensitivity of the material. We could describe the structure as 1D long-range ordered and 2D disordered, which culminates in a mixture of four types of domains.
 
By using such an approach, we not only demonstrated the general procedures for ab initio structure elucidation of disordered nanocrystals, but also the potential that the combination of SCED, HRTEM and XRPD offers.