Thorium -nitride

N4Th3 (s) TII3N4 (S) Thorium Nitride N4TII3 (s) Th3N4 (s)... 

Uranium and thorium nitride halides are related to the above. The series A/N.Y (M = U. Th A = Cl. Br, I) have the PbFCI structure (see Fig. 23) [246, 247. 248]. The corresponding fluorides have the LaOF structure [249, 250] which is an ordered superstructure of fluorite with a rhombohedral or tetragonal distortion [251, 252]. UNF and I hNF. therefore, crystallize with MN4F4 cubes while the anions center the tetrahedral sites (see Fig. 24). Yellow ThNH crystallizes on a face-centered cubic lattice [253]. 

Boron nitride Chromium nitride Hafnium nitride Niobium nitride Tantalum nitride Thorium nitride... 

X.l Nitrogen compounds and complexes X.1.1 Solid and gaseous thorium nitrides... 

Sato, S.-L, Specific heats of thorium nitride, lithium nitride and zinc nitride, Sci. Pap. Inst. Phys. Chem. Res. (Jpn.), 35, (1939), 182-190. Citedonpages 312,412,413. 

Auskem, A. B., Aronson, S., Electrical properties of thorium nitrides, J. Phys. Chem. Solids, 28, (1967), 1069-1071. Cited on page 309. 

BOW/ARN] Bowman, A. L., Arnold, G. P., Crystal stracture of thorium nitride [ThsNJ, Acta Crystallogr., B27, (1971), 242-243. Cited on page 312. 

Kusakabe, T., Imoto, S., Thermal decomposition of thorium nitride and dithorium dinitrogen oxide, Technology Reports of Osaka University, Report 22, (1972). Cited on pages 310,313,535. 

Thorium nitride Is usually prepared by heating Th filings in a stream of dry, pure Ng. The reaction is complete in three... 

Although some of these saltlike nitrides have high melting points (for instance, thorium nitride 2820"C uranium nitride 2800°C plutonium nitride 2550 beryllium nitride 2200 C barium nitride 2200"C), they are sensitive to hydrolysis and react readily with water or moisture to give ammonia and the corresponding metal oxide or hydroxide. Consequently, they do not meet the refractory requirements as interpreted here. Some of these nitrides are useful industrial materials particularly as sintering additives for the production of silicon nitride, aluminum nitride, and cubic boron nitride (see Ch. 14). 

Thorium.— All but one of the thorium compounds reviewed are complex fluorides and, not unexpectedly, contain Th. The exception is thorium nitride, which has been studied by neutron diffraction of the powder. The structure comprises an hhc close-packed arrangement of thorium atoms, with nitrogen atoms in some tetrahedral sites between h and h layers and some octahedral sites between h and c layers. Th-N distances are 2.31— 2.47 A for nitrogen atoms in tetrahedral sites and 2.53— 2.91 A for nitrogen atoms in octahedral sites. 

Thorium Nitride. Three nitrides have been reported ThN, m.p. 2650°C ... 

Previous reviews of thorium nitrides are the early work in the Gmelin Handbook [13], the physical properties as tabulated by Peterson, Curtis [14], the tabulation and contributions to the thermochemical data by Rand [15], their brief mention in an engineering data tabulation of nitrides [16], and a chapter on thorium nitrides in High-Temperature Nuclear Fuel [17]. 

For further thermodynamic data see Table 12 and Phase Relations , p. 57. The brownish yellow compound ThNH is stable in air and dissolves slowly in warm 4N HCl with evolution of gas assumed to be H2 [1]. Yellow ThNi 2H crystals are more resistant to aqueous media than the binary thorium nitrides, and Th-N-H compounds [2]. 

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