 In the polysilenes and the polysilynes, the backbone is made exclusively of silicon atoms; the pendent- or side-groups, are not shared between skeletal atoms of the backbone chain.Compression of silane itself under extremely high pressures (> 90 GPa) for long periods of time (~8 months) produces a material that differs from those shown above in that the silicon atoms are not bonded to one another but, rather, are connected via bridging hydrogen atoms.The silicon atoms are 8-fold coordinated by hydrogen (i.e.