Tungsten Hexanitride with Single-Bonded Armchairlike Hexazine Structure at High Pressure

{\mathrm{WN}}_{6}phase discovered at 126--165 GPa after heating of W in nitrogen. XRD refinements reveal a unit cell in space group R\overline{3}mwhich is consistent with the {\mathrm{WN}}_{6}structure with armchairlike hexazine ({\mathrm{N}}_{6} rings, while strong {A}_{1g}Raman mode confirms its \mathrm{N}─\mathrm{N}single bonds. Density functional theory (DFT) calculations reveal balanced contributions of attractive...