Calculated electronic structures and chemical bonding in Sc and Y carbides.

Zhukov V.P., Gubanov V.A., Jepsen O., Christensen N.E., Andersen O.K.

The energy band structures of ScCx and YCx for x=1.0, 0.75, and 0.5 are calculated self-consistently by the LMTO method. From the total energies, the theoretical values of the lattice constants and the energies of vacancy formation are determined. It is shown that in YCx for x>0.7 the metalloid vacancies are stabilized energetically and it is suggested that vacancies in YCx for x<0.7 and in ScCx for all x are formed when the compounds are synthesized at high temperature and they persist at low temperatures as a result of quenching. Furthermore the changes in the energy band structures are studied and cohesive properties of these compounds when carbon is substituted by oxygen or nitrogen.

Physica Status Solidi B, 143 173-84, 1987.

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