Correlation between electronegativity and superconductivity

This paper brings out one of the striking features exhibited by all oxide superconductors. It is found the irrespective of the value of $T_c$, the average electronegativity χ of all the oxide superconductors found up until now lie between 2.5 and 2.65 in the Pauling’s scale and this is considered to be one of the criteria for oxide materials to be considered superconductors. This narrow range is in contrast to the elemental superconductors whose values lie in a broad range from 1.3 to 1.9. Further, the pressures required to drive some of the elemental metals to become superconductors have been calculated on the basis of their electronegativity values. The pressures so obtained agree well with the experimental observations and those calculated on the basis of band theory. The average electronegativity of A–15 Chevrel-phase superconductors are also given. Based on the concept of electronegativity the other oxide systems which are likely to become superconductors have been suggested.