Extended Data Fig. 4 | High-angle annular dark f ield images and energy-
dispersive spectroscopy data for 1(FeCl 2 ) 19. a, High-angle annular dark field
(HA ADF) image (a, top left) and energy-dispersive X-ray spectroscopy (EDS)
mapping Zr (a, top right; yellow), Fe (a, bottom left; orange) and Cl (a, bottom
right; green of a microcrystalline powder sample of 1 (FeCl 2 ) 19. b, STEM-EDS line
scan analysis for Fe (orange) and Zr (yellow) across the length of the crystallite
plotted as normalized atom per cent. The average amount for the two elements
was determined to be 77 ± 9% for Fe and 23 ± 9% for Zr, corresponding to a Fe:Zr
ratio of 3.3. c, EDS spectrum for the crystallite of 1 (FeCl 2 ) 19. Signals for Cu and
Au originate from the space-filling washer and sample grid, respectively.