Powder samples were prepared for electron microscopy by first suspending them in isopropyl alcohol (IPA) followed by sonication for 10 minutes. The suspension was then drop-cast onto coppersupported C-flat grids (Protochips). Annular dark field scanning transmission electron microscopy (ADF-STEM) tomography and Xray energy dispersive spectroscopy (EDS) was carried out using an FEI Titan Themis 300 (ThermoFisher) at the University of Leeds, equipped with a Super-X (Bruker) four-detector EDS system and an 'X-FEG' high brightness electron source. The microscope was operated at 300 kV. ADF-STEM images were acquired across a tilt range of -75 o to +65 o , with a tilt angle increment of 2 o . EDS maps were acquired at 0 o tilt for both samples after the acquisition of the tilt-series to avoid degradation of the tilt-series data from any electron beam-induced changes to the sample (beam damage) from increased electron fluence required for EDS mapping. Details on image processing can be found in the Supplementary information.