Germanium polymer backbone

Group IVA starts with carbon, which is a nonmetal, followed by silicon and germanium, which are metalloids (semimetals), and tin and lead, which are metals. All of the group IVA elements have the ability to catenate however, as you move down the group, this ability decreases. Some of the more important inorganic polymers are polysilanes, in which there are repeat Si-Si units in the polymer backbone. However, the bond energy of Si Si bonds is 222 kJ/mol, while the... 

Small et al. described the synthesis of pentacoordiante and hexacoordinate spiropolygermylate ionomeric materials where germanium is contained in the polymer backbone. These materials are air stable, nonhygroscopic, amorphous powders. The hypervalent germanium functionality was verified by Ge and solid-state and solution NMR, proton solution NMR, and IR spectra. The powders are stable to about 325°C. 

---