Hafnium nitrides
The hafnium nitrides are the various salts produced from combining hafnium and nitrogen. The two most important such are hafnium(III) nitride, HfN; and hafnium(IV) nitride, Hf3N4. None can be prepared from 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 refractory and generally produced as a thin film coating,[2] although zone annealing gives the bulk material.[3] HfN adopts the rock-salt crystal structure.[2] The surplus hafnium electron delocalizes, so that HfN is a metal, conducting at room temperature and superconducting below 8.8 K (−443.83 °F). Its bright gold color is a cheaper alternative to gilding.[4]
The dark red semiconductor Hf3N4 does not form at room temperature, but requires high pressure, high temperature synthesis in a diamond anvil cell. At 18 GPa (180,000 atm) and 2,800 K (4,580 °F), it adopts the cubic crystal structure and repeats according to space group I{{{1}}}3d.[2] At lower pressures, the cubic structure is believed 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]
References
- ^ Bazhanov, D. I.; Knizhnik, A. A.; Safonov, A. A.; Bagatur’yants, A. A.; Stoker, M. W.; Korkin, A. A. (2005-02-15). "Structure and electronic properties of zirconium and hafnium nitrides and oxynitrides". Journal of Applied Physics. 97 (4). doi:10.1063/1.1851000. ISSN 0021-8979.
- ^ a b c Zerr, Andreas; Miehe, Gerhard; Riedel, Ralf (2003-03-01). "Synthesis of cubic zirconium and hafnium nitride having Th3P4 structure". Nature Materials. 2 (3): 185–189. doi:10.1038/nmat836. ISSN 1476-1122.
- ^ Christensen, A. Nørlund; Kress, W.; Miura, M.; Lehner, N. (1983-07-15). "Phonon anomalies in transition-metal nitrides: HfN". Physical Review B. 28 (2): 977–981. doi:10.1103/PhysRevB.28.977. ISSN 0163-1829.
- ^ a b Kroll, Peter (2003-03-25). "Hafnium Nitride with Thorium Phosphide Structure: Physical Properties and an Assessment of the Hf-N, Zr-N, and Ti-N Phase Diagrams at High Pressures and Temperatures". Physical Review Letters. 90 (12). doi:10.1103/PhysRevLett.90.125501. ISSN 0031-9007.
- ^ a b Zhang, Jin; Oganov, Artem R.; Li, Xinfeng; Niu, Haiyang (2017-01-18). "Pressure-stabilized hafnium nitrides and their properties". Physical Review B. 95 (2). doi:10.1103/PhysRevB.95.020103. ISSN 2469-9950.
- ^ Ushakov, Sergey V.; Navrotsky, Alexandra; Hong, Qi-Jun; van de Walle, Axel (26 Aug 2019) [6 Aug 2019]. "Carbides and nitrides of zirconium and hafnium". Materials. 2019 (12). Basel: MDPI. doi:10.3390/ma12172728.
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NH3 N2H4 +H HN2− H2N− | He(N2)11 | ||||||||||||||||||||
Li3N LiN3 | Be3N2 Be(N3)2 | BN -B | C2N2 β-C3N4 g-C3N4 CxNy | N2 | NxOy +O | N3F N2F2 N2F4 NF3 +F | Ne | ||||||||||||||
Na3N NaN3 | Mg3N2 Mg(N3)2 | AlN | Si3N4 -Si | PN P3N5 -P | SxNy SN S2N2 S4N4 SN2H2 | NCl3 ClN3 +Cl | Ar | ||||||||||||||
K3N KN3 | Ca3N2 Ca(N3)2 | ScN | TiN Ti3N4 | VN | CrN Cr2N | MnxNy | FexNy | Co3N | Ni3N | Cu3N | Zn3N2 | GaN | Ge3N4 -Ge | AsN +As | Se4N4 | Br3N BrN3 +Br | Kr | ||||
RbN3 | Sr3N2 Sr(N3)2 | YN | ZrN | NbN | β-Mo2N | Tc | Ru | Rh | PdN | Ag3N | Cd3N2 | InN | Sn | SbN | Te4N4? | I3N IN3 +I | Xe | ||||
CsN3 | Ba3N2 Ba(N3)2 | * | LuN | HfN Hf3N4 | TaN | WN | RexNy | Os | Ir | Pt | Au | Hg3N2 | Tl3N | (PbNH) | BiN | Po | At | Rn | |||
Fr | Ra3N2 | ** | Lr | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og | |||
* | LaN | CeN | PrN | NdN | PmN | SmN | EuN | GdN | TbN | DyN | HoN | ErN | TmN | YbN | |||||||
** | Ac | ThxNy | PaN | UxNy | NpN | PuN | AmN | CmN | BkN | Cf | Es | Fm | Md | No |