应用固体与分子经验电子理论(EET)计算BaTiO3,BaZrO3,PbTiO3,PbZrO3,KNbO3,NaNbO3,CaTiO3,SrTiO3 8种典型立方相钙钛矿氧化物的价电子结构,并讨论晶体中各组成原子的实际价电子数。计算结果表明:8种钙钛矿氧化物的价键电子结构表现为离子性和共价性的混合,原子的种类是影响化合物价电子结构的重要因素,而相同的晶体结构决定了价电子分布的相似性;组成晶体的原子的实际价电子数与标准自由离子电荷有差异,且具有与玻恩有效电荷相似的特点。
The valence electron structures (VES) of eight types of cubic perovskite ferroelectrics were investigated by using the empirical electron theory(EET) of solids and molecules. The atomic charges in actual crystals were calculated. The results demonstrate that the VES revealed the co-existence of the ionic-covalent characters in the VES of perovskite compounds. In the crystal of perovskite compounds, the kind of atoms is the main factor of leading to the different electron structure. The same crystals structure determines the similarity of the valence electron distribution. The actual valence electron number is different from the nominal ionic charges. The actual valence electron number has the similarity to Born effective charges.