  We use the term "bond polaron" for a phonon coupled entity which makes the
link between neighboring conductive CuO_2 layers in high-Tc superconductive
materials. The link is essential for the superconductivity which requires a
long range phase coherence in addition to pairing of carriers. The linkage
features studied point to a process which is less dependent on the doped hole
density implanted as x in the solid solution. The analysis applies to single
layered materials mostly but may help understand multilayer ones as well.
