Raman spectral study of the synthesis glass formation, structure and phase separation of Si(x)Se(1-x) glasses and the SiSe2 crystalline solid.

Crystalline SiSe2 and a series of Si(x)Se(1-x) clear yellow- orange glasses (0.33 x = 0.4) were synthesized and studied by Raman spectroscopy. Spectra of crystals were analyzed in terms of the known crystal structure of SiSe2 whereas for the glasses a new cross-linked chain-cluster model (CLCC) is proposed and is the basis for extensive spectral analysis. Extended chain-only and random network models are inconsistent with the data. The CLCC model is characterized by well defined chains of edge-sharing (SiSe4) tetrahedra, like in the crystal, which are cross-linked via corner-sharing (SiSe4) tetrahedra to form very large highly viscous inorganic polymers.