High-pressure synthesis and crystal structures of β-MNX (M = Zr, Hf; X = Cl, Br, I)

The single crystals of six kinds of metal nitride halide, beta-MNX (M = Zr, Hf; X = Cl, Br, I), were grown in sealed Au (or Pt) tubes by the reaction of MN or MNX powders with NH4X as fluxes under high-temperature and high-pressure conditions such as 3-5 GPa at 900-1200degreesC. The x-ray structure analysis revealed that all six kinds of compound crystallize in a rhombohedral space group R (3) over barm, Z = 6. beta-ZrNCl, beta-ZrNBr, and beta-HfNCl are isotypic with SmSI, and the others isostructural with YOF.