摘要
为了说明碱金属卤化物 (MX)气态时原子间距离小于晶体中原子间距离这种普遍现象 ,通过离子性数量 ,说明MX中也存在着一定的共价性 ,气态MX中原子间距小于晶体中原子间距正是由于共价键的贡献所致 .运用分子轨道理论 (MOT)和回归分析得出MX成键原子轨道 (BAO)能级差 (ΔE)与MX性质之间的线性关系式 :y =a +bΔE ,其中 y代表MX的性质诸如键长 ,键能 ,熔点 ,ΔfG m,ΔfH m等 ,a和b为特征常数 ,此式的线性相关系数为± (0 .985± 0 .0 15 ) ,计算结果与文献报道的实验值吻合良好 ,有 97%的相对偏差小于 4%
The common phenomenon that the inter atomic distances in gaseous alkali metal halide (MX) are less than those in crystal is just because of the existence of covalent bond in MX, which can be explained based on the ionic number. With molecular orbital theory and regression analysis, the general linear regression equation y = a + b Δ E (the relation between Δ E of BAO and MX properties) was obtained, where y stands for MX properties, such as bond length, bond energy, melting point, Δ fG m , Δ fH m and so forth, a and b are characteristic constants. The linear correlation coefficient of the formula is ±(0.985±0.015). The results calculated by the formula are in good agreement with the experimented values in the literature. For example, 97% of the total calculated results have relative errors less than 4%.
