Lanthanum dicarbide

Rare earth dicarbides are commonly formed in the rare-earth (except for europium)-carbon systems. Many investigators, in particular Atoji, have made a great contribution to the determination of the structure of RC2. The neutron diffraction investigations on the structure of the rare earth dicarbide, first by Atoji and Medrud (1959) showed that for the lanthanum dicarbide the atomic coordinates in the unit cell are (000, ) + (OOz) for carbon atoms and z = 0 for lanthanum atoms, and the carbon positional parameter z(A) is 0.403 + 0.002, corresponding to a well-defined minimum at a C-C distance of 1.28 0.03 A. LaC2 can probably be described approximately in terms of ions, with the extra electron in a conduction... 

The thermodynamic study of rare earth dicarbide systems is essential in rmderstanding the chemical state of fission products in the mixed carbide fuels used in fast breeder reactors. Thermodynamic properties of one such carbide, lanthanum dicarbide (LaC2) in the temperature range 1263-1543 K have been determined by using the new method referred to above. 

Lancasta microindentation tester, 50 Lanthanide dicarbides pendulum hardness, 295 Vickers hardness, 304 Lanthanum boride, LaB , 297 Lanthanum oxide (1 03) effect on silica hardness, 238 as network modifier, 238 Lanthanum silicate (La2 i207) hardness, 242 precipitate in silica, 238 Lateral vent crack, 55, 126, 148, 154, 158-161, 235 analysis of, 159-161 circular contours of, 159 critical flaw size, 154 length as a function of load, 161 and surface distortion, 159 at thin film interfaces, 205 Lattice energy and fracture energy, 198 and hardness, 22, 24 of silicon, 24... 

---