INVESTIGATION OF EMPIRICAL LAWS FOR SUPERCONDUCTIVITY OF ALLOY AND COMPOUND SUPERCONDUCTORS

By studying the average effect of the electronegativity of alloy and compound superconductors, some empirical laws are found. The average value of the electronegativity of alloy superconductors \overline\chi is from 1.3 to 1.9, most of which is concentrated in the region 1.5<\overline\chi<1.8. The \overline\chi of many higher T_c superconductors is nearly 1.60. All these characteristics are similar to element superconductors. The average value of the electronegativity \overline\eta of positive valence elements in oxide superconductors is from 1.3 to 1.6, and the average effect of an electronegativity of zero on every element \overline\zeta is from 1.75 to 2.00. The mean of \overline\eta and \overline\zeta is from 1.5 to 1.8. When both \overline\eta and \overline\zeta are near the limit value (1.3 or 1.6 and 1.75 or 2.00), the material has a very low T_c, even is non-superconductive. The \overline\eta of other compound superconductors is either too high or too low, and the \overline\zeta is too low so that the T_c of these superconductors is quite low. Studying the average effect of the electronegativity of non-superconducting compounds further confirms the laws.