Powder X-ray diffraction measurements on bulk EPI powder were performed on a Siemens D500 diffractometer in a Bragg–Brentano configuration. A Cu sealed tube (λ = 1.54 Å) was used, with the beam guided through a slit system before the sample; a secondary graphite monochromator was then used in front of a scintillation detector. The simulated powder diffraction pattern for the structure of EPI solved from the thin film was generated using the Mercury (CCDC) software package, which was also used for crystal structure visualization.19