The valence electronic structures of tantalum carbide (TaC) and tantalum nitride (TaN) are studied by using the empirical electronic theory (EET). The results reveal that the bonds of these compounds have covalent,metallic and ionic characters. For a quantitative analysis of the relative strength of these components,their ionicities have been calculated by implanting the results of EET to the PVL model. It has been found that the ionicity of tantalum carbide is smaller than that of tantalum nitride. The EET results also reveal that the covalent electronic number of the strongest bond in the former is larger than that of the latter. All these suggest that the covalent bond of TaC is stronger than that of TaN,which coincides to that de-duced from the first-principles method.
FAN ChangZeng1,2,SUN LiLing2,WEI ZunJie1,MA MingZhen3,LIU RiPing3,ZENG SongYan1 & WANG WenKui3 1 Department of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China
