Uranium dicarbide

Metal acetylides or carbides Calcium carbide 3.97/46 See Caesium acetylide Mineral acids Rubidium acetylide Acids Uranium dicarbide Hydrogen chloride... 

Lithium acetylide Halogens Monocaesium acetylide Monorubidium acetylide Strontium acetylide Halogens Uranium dicarbide Halogens Zirconium dicarbide Halogens See Monolithium acetylide-ammonia Gases... 

Monocaesium acetylide and caesium acetylide, lithium acetylide and rubidimn acetylide, tungsten carbide and ditungsten carbide, and zirconium dicarbide all ignite in cold fluorine, while uranium dicarbide ignites in warm fluorine. 

Rubidium acetylide ignites on heating, and uranium dicarbide incandesces in the... 

Trimercuiy tetraphosphide, 4616 Tungsten carbide, 0563 Uranium carbide, 0562 Uranium dicarbide, 1028 Zinc phosphide, 4876 Zirconium dicarbide, 1029 METAL PNICTIDES... 

Uranium Dicarbide. UC2 mw 262.05 metallic crysts mp 2350—2400° bp 4370° d 11.28g/cc at 16°. Decompd by dil inorg acids, and v violently by w. Prepn is by heating a mixt of U oxide and sugar charcoal at 1370° in a C crucible by means of an electric furnace for 5 to 10 minutes. The compd emits brilliant sparks on impact, and ignites on grinding in a mortar or on heating in air to 400°. In particle sizes of less than 40 microns, it is spontaneously flammable. The dicarbide reacts with incandescence with halogens or N2 above 300°... 

The fuel particles used in these studies were typical pyrolytic carbon-coated thorium-uranium dicarbide, (Th,U)C2, microspheres. The kernels, — 200/i in diameter, were prepared from Th02, U02, and C and converted to the carbide at temperatures below 2200°C., followed by a spheroidization above the melting point, 2450°-2500°C. The bare kernels were coated with a 30-50fi layer of low density (— 1.0 gram/cm.3) buffer pyrolytic carbon, followed by a 40-70/a layer of high density... 

Tetraamminelithium dihydrogenphosphide, 4590 Thorium dicarbide, 1023 Titanium carbide, 0558 Trimercury tetraphosphide, 4611 Tungsten carbide, 0560 Uranium carbide, 0559 Uranium dicarbide, 1024 Zinc phosphide, 4870 Zirconium dicarbide, 1025 METAL ACETYLIDES N-METAL DERIVATIVES METAL HYDRIDES METAL OXIDES METAL SULFIDES NITRIDES... 

The dicatbide, either by itself, mixed with uranium dicarbide, or in solid solution with uranium dicarbide, is used as fuel material in some versions of high-temperature gas-cooled reactors. Like uranium carbides, the thorium carbides react rapidly with water or moist air and must be protected from moisture in storage and fuel fabrication. 

Holley et al. [1984HOL/RAN] give another (five-parameter) estimate by comparison specifically with uranium dicarbide (which has a pronounced upward curvature in the heat capacity at high temperatures). For convenience, their equation has been refitted to two extended Kelley equations to conform to NEA usage... 

As in the mixed rare earth dicarbide systems, the rare earth dicarbides also form a solid solution with uranium dicarbide and there exists a composition dependence of the cubic-to-tetragonal phase transformation for the UC2-LaC2 or the UC2 CeC2 solid solutions (McColm et al. 1972), as well as for the UC2-GdC2 solid solution (Wallace et al. 1964). 

PasquaUni, E.E., Adelfang, P., and Nunez Regueiro, M., Carbon nanoencapsulation of uranium dicarbide, J. Nucl. Mater., 231, 173-177, 1996. 

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