Bixbyite-type phases in the system Ta-Zr-O-N

Phase-pure tantalum/zirconium oxide nitrides and nitrides were synthesized by the ammonolysis of amorphous oxide precursors. The nitrogen-rich oxide nitrides with variable anion composition and the nitride TaZrN3 crystallize in the cubic bixbyite-type structure (space group Ia (3) over bar). The nitrogen content of these compounds has a significant influence on the cell parameters, the atomic positions, and the optical band gap. The results extend the already well-studied Ta-Zr-O-N system by new oxide nitrides in addition to the already known bad-deleyite- and anosovite-type phases. TaZrN3 can be considered as a thermodynamically stable ternary variant of metastable Ta2N3.