PXRD measurements were conducted on a Stoe STADI P Transmission Powder Diffractometer with a Cu Kα X-ray source and a primary monochromator in transmission geometry. Borosilicate glass capillaries with an outer diameter of 0.7 mm and a wall thickness of 0.01 mm were used for 10 all measurements. All measurements were conducted under air, except Mo-containing samples, for which capillaries were packed inside an argon-filled glovebox and sealed with vacuum grease before measurement. Space group, symmetry and unit cell parameters were determined by fitting the reflection positions and intensities of the measured powder patterns via the Le Bail approach implemented in the program package TOPAS V6 (Bruker AXS GmbH, Karlsruhe, Germany) 67 .