sentences:  The double tetrahedron structure (coordination) is sharing one oxygen anion O2−, whereas in the Si-O-Si- molecular structure, the covalent bond is achieved through Si and O co-sharing only one electron.This results in stronger bond within the latter structure.The American mineralogist and geochemist G. V. Gibbs and his team studied the polymeric bond Si-O-Si-O and stated in 1982-2000