Zirconium scandium oxide nitrides: Formation and decomposition followed in situ by XRD and thermal analysis

The dark green powder of Zr50Sc12O43N50 was produced from Zr50Sc12O118 under a constant flow of ammonia. Zr50Sc12O43N50 crystallizes cubic with space group image and image in the C–M2O3 structure (bixbyite structure). The reaction path was followed by in situ X-ray diffraction and showed that the substitution of 3O2− by 2N3− generates additional vacancies on the anion sites in the fluorite basis structure. On the way to the bixbyite structure time- and temperature-controlled X-ray diffractograms revealed the known fluorite-related superstructures (i.e. the vacancy distribution) for the compositions image and image. The reverse process, i.e. the oxidation of the oxide nitride was followed in DTA/TG experiments exhibiting the different vacancy orderings at 420, 500 and image.