Table 3: HTSC data for the McMillan-Hopfield parameter.

ExTc2 Tc

2Tl ( )12567.659.61253.249.34.9
2Tl ( )10757.965.21122.3 38.43.9
2Tl ( )8043.376.6900.0 25.92.8
Y1239249.851.2936.422.63.5
2Bi ( )8948.259.2795.421.63.4
Nd ( )8445.553.591220.33.1
La ( ) 4021.756.8501.86.7 1.75
Nb3Sn189.7599.3357.27.9 1.67
Pb7.23.920731.42.4 1.55