W_2C相的价电子结构与性能的关系

Valence Electron Structure and Eigen-Properties of W 2C Phase

根据固体与分子经验电子理论，对Ｗ２Ｃ相的价电子结构进行了定量分析，通过键距差方法计算了Ｗ２Ｃ晶体中各键上的共价电子数。结果表明，近似平行于ｃ轴最近邻的Ｗ－Ｃ原子键最强，其共价电子数ｎＡ＝０．６９９２５，键能ＥＡ＝１４１．２７ｋＪ／ｍｏｌ；近似平行于ｃ轴的Ｗ－Ｗ原子间结合力次之，其共价电子数ｎＧ＝０．２０８３４，键能ＥＧ＝４６．２４ｋＪ／ｍｏｌ；位于（０００１）面上的Ｗ－Ｗ原子键也较强，该键上共价电子数ｎＥ＝０．１６６２２，键能ＥＥ＝３６．０８ｋＪ／ｍｏｌ。依据计算结果分析了Ｗ２Ｃ相高硬度、高熔点的原因。

The valence electron structure of W 2C phase has been studied on the basis of Yu′s empirical electron theory of solids and molecules The values of valence electron on each bond in W 2C crystals are calculated by the method of bond length difference (BLD) The results show that the bonds between the nearest W-C atoms nearly parallel to the c axis are the strongest, and the value of valence electron n A=0 69925 and the bond energy E A=141 27kJ/mol The bonds between the W-W atoms nearly parallel to the c axis are the strong ones, and the value of valence electron n G=0 20834 and the bond energy E G=46 24kJ/mol Furthermore, the bonds between the W-W atoms distributed on the (0001) plane are also the strong ones, for which n E=0 16622 and E E=36 08kJ/mol The eigen-properties of high hardness and melting point are explained with the calculated results for W 2C phase