Hafnium nitrides
The hafnium nitrides are the various
hafnium oxide, but must instead be prepared from the elemental metal or a different hafnium nitride salt; attempted nitridation of the oxide gives an oxynitride instead.[1]
HfN is
superconducting below 8.8 K (−443.83 °F). Its bright gold color is a cheaper alternative to gilding.[4]
The
metastable, decaying to the orthorhombic structure of zirconium(IV) nitride.[4][5] That structure forms outright at 19 GPa and 2,000 K (3,140 °F), and another metastable tetragonal structure forms at 12 GPa and 1,500 K (2,240 °F). Computational studies suggest that it may catalyze polymerization of nitrogen at very high temperatures, through a catenary anion in HfN10.[5]
In systems with limited nitrogen, hafnium also forms Hf3N2, as well as a solid solution hafnium alloy.[6]