Structural hypotheses and Raman spectroscopy investigations of glasses belonging to the B₂S₃ Li₂S LiI system

Abstract

A previous ¹¹B nuclear magnetic resonance investigation of glasses belonging to the B₂S₃-Li₂S-LiI system had allowed the authors to determine the variation of the number of three and four coordinated boron atoms with composition. These results, in addition to the observation that vitreous B₂S₃ quite easily forms fibres during casting, have led us to propose structural hypotheses for B₂S, based glasses, which are supported by the present Raman spectroscopy study. For vitreous B₂S₃ the spectra were accounted for on the basis of the various type of BS_3/2 triangles proposed by the model. Molecular orbital considerations allowed us to assign the most significant lines for the binary glasses by assuming that BS_3/2 triangles (with or without nonbridging sulphur atoms) and BS₄ tetrahedra were present. In the ternary system, lithium iodide has been found to interact slightly on the structural entities, altering their vibrational characteristics without fundamentally modifying their nature.