Universal Correlations of Tc Ion Mass Scaling with Distance

We present a short overview of the critical temperature correlations with different parameters for low and high T_c superconductors. The overview underlines the importance of crystalline structure in determining the critical temperature value. The structure of copper-based superconductors is studied in comparison with low-temperature superconductors and a new correlation of the transition temperature is found. Namely, the layered structure, more exactly a certain distribution of the mass of the ions along the c-axis is the key factor in determining the intrinsic critical temperature, parameter introduced by Kresin et al. [4].