共价性对卤化银性质的影响

The Effect of Ionic Bond with Partical Covalent Character on the Properties of Silver Halide

为了定量说明卤化银 (Ag X)性质受其共价性的影响 ,采用分子轨道理论 (MOT)和线性回归法对此加以讨论 ,探讨成键原子轨道 (BAO)之间能级差 (△E)与 Ag X性质的定量变化规律 ,分别求得 Ag X的键长、晶格能、生成热、溶解度、溶度积、络合反应平衡常数的变化规律线性关系式 ,即 :y=a+b△ E,其中 y代表 Ag X的性质 ,a,b分别为特征常数 .所得 6个线性回归方程的线性相关系数绝对值变化区间为 0 .981 0～ 0 .9986,由这些方程求得的结果与文献报道的实验值之间的相对偏差小于 9.5%的占近 91 % 。

Why is the experimental lattice energy of silver halide(AgX) greater than calculated one? also why is the AgX bond length less than ionic radius sum( r Ag + + r X - )? Because the Chemical bond in AgX is not 100% ionic bond and it is ionic bond with partical covalent character. The six relational expressions, which are between energy level difference(△ E ) of bonding atomic orbitals in AgX and the properties of silver halide, are given by using the molecular orbital theory(MOT) and the linear regression method. Their greneral expression is as following: y=a+b△E. Where y stands for lattice energy( L 0), bond length( BL ), standard formation heat(△ fHm ), solubility product, equilibrium constant of complex reaction and so on. The correlation coefficients of given equations are 0.9810≤IRI≤0.9986, the relative errors between the y values obtained from the linear regression equations and experimental results are less than ±9.5%. They are close upon 91% in the total calculated results. This means the theory calculation is agree with experiment results.