We have systematically studied the mechanical stability of group V transition
metal carbides TMC2 (TM = Hf, Ta, W, Re, Os, Ir, Pt, and Au) in the pyrite
and fluorite phase, by calculating their elastic constants within the density
functional theory scheme. It was found that all but ReC2 and OsC2 are
stable in pyrite phase. On the other hand, all metal carbides studied were
unstable in the fluorite phase.Comment: 7 pages, 4 figure