SPECTROSCOPIC STUDIES OF 5-COORDINATE SILICON-COMPOUNDS

A detailed study of the structural and chemical features of a series of novel compounds in which silicon is in 5-coordination with respect to oxygen has been carried out using XRD, FTIR, solid-state NMR, and ESCA. All compounds contain glycolate groups and different charge-balancing alkali-metal cations. NMR confirms that only 5-coordinate Si is present. There is a unique set of ESCA core level binding energies for these materials. Peak positions may be influenced by (1) the coordination number of Si, (2) the presence of organic moieties, and (3) the kind and concentration of cations. All binding energies in the 5-coordinate silicon compound with Cs+ are shifted with respect to those in other compounds to suggest that effects (1) and (3) are dominant.