| Abstract: In this paper the electric index (fi) of combined atom is defined as fi=m2i·xpi·(n*i)-0.5. fi has defineated the primary factors to affect hydrated heat of metal ion (ΔHh) and solubility of metal hydroxide (pKm). Their relation formulas are set up by least square method: -ΔHh=260.31+519.31fi, n′=51, r=0.9693; pKm=0.0285+1.1358fi, n′=46, r=0.9642. The calculated values of pKm are better than the documental method. The electric connectivity index ( mF) is built up with fi, and among them the formulas of zero, first order index are defined as 0F=Σ(fi)0.5, 1F=Σ(fi·fj)0.5 respectively. 0F and 1F have highly correlativity for lattice energies (U) of inorganic compounds. Their linear regression equations are proposed as follows: (1) for 47 inorganic compounds, U=-228.41+407.620F+169.381F, R=0.9985; (2) for 34 main group compounds, U=-420.39+507.720F+144.961F, R=0.9992; (3) for 13 transitional element halides, U=573.80-119.970F+458.581F, R=0.9984. The predicting values by 0F and 1F basically tally with the experiment values, and are even more ideal than the theoretical values of document. |
