Tungsten mononitride

Another structure is the simple hexagonal structure (hex) such as that of tungsten mononitride (8WN) where the metal atom layers form a sequence of layers AA or BB. Such structures are not close-packed and do not form octahedral sites the available interstitial sites are trigonal prisms (see Fig, 3.13 of Ch. 3). This structure cannot form if the ratio of the nitrogen/ metal atomic radii is small, as is the case in the Zr-N and Hf-N systems. 

Gray solid. Slowly hydrolyzed by water. Tungsten mononitride... 

In the case of the nitrides and carbides the structures have some effect on the electric properties. For compounds that have an NaCl structure, the mononitrides and carbides are better metallic conductors than the metals themselves. Those that have zinc blende or Wiirtzite structures (SiC, AIN, InN) or other (SigNJ are useful semiconductors or insulators. Tungsten carbide when sintered with cobalt shows some catalytic activity in fuel cells. This hybrid composite is so hard and tough that it is widely used in drill bits for concrete drilling. 

Zirconium Diboride (ZrB2) Chromium Diboride (CrB2) Titanium mononitride (TiN) Tungsten Monocarbide (WC) Knoop lOOg 1560 kg/mm Knoop lOOg 1700 kg/mm Knoop lOOg 1770 kg/mm Knoop lOOg 1870-1880 kg/mm ... 

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