valence electron
5.The valence electron structures of in termetallic compounds Mg3Cd and MgCd3 have eben analysed with the empirical electron theory of solids. It is shown that the mechanical properties of crystals are determined by the covalent electron number nc and the ratio of covalent electron number to total number of valent electron η.
10.Based on the elememtal electronegative,bonding p electron number,the valence electron number,main quantum number of the outermost shele orbital in atom,molecular connectivity indexes(0X and 1X)have been developed for research on the standard enthalpies of formation for 115 ABn compounds in gas state in this paper.

