The new ternary nitrides BaHf 1؊x Zr x N 2 (04x41) have been synthesized by the solid state reaction of the binary nitrides Ba 3 N 2 , HfN, and ZrN and characterized by powder X-ray diffraction. The crystal structure of the end member, BaHfN 2 , has been refined from powder data. The nitridohafnate crystallizes in the tetragonal space group P4/nmm (a ؍ 4.1279(1) A s , c ؍ 8.3816(4) A s , Z ؍ 2) and is isostructural with the oxide KCoO 2 . Hafnium is coordinated to five nitrogens in a distorted square base pyramidal geometry, forming layers of edge-sharing pyramids which stack along the c axis. Barium is situated between the Hf-N layers and is coordinated to five nitrogen atoms. Samples exhibit temperature-dependent paramagnetism between approximately 8 and 293 K and become superconducting below 8 K.
1998 Academic Press . The latter tantalum material has attracted particular interest on account of the superconducting transition reported in this nitride at ca. 9.6 K. Magnetic measurements conducted on SrZrN and SrHfN suggest these materials are intrinsically diamagnetic at room