Short range structure of B2O3–Cs2O glasses analyzed by x-ray diffraction and Raman spectroscopy

Abstract

Structural analyses of pure B2O3, B2O3(90 mol%)–Cs2O (10 mol%) and B2O3 (80 mol%)–Cs2O (20 mol%) glasses were made by an x-ray diffraction method and the effects of Cs2O addition were investigated on the short range structure of the glasses. Furthermore, Raman spectroscopic studies were applied to analyze the interatomic interactions between boron and oxygen atoms. Due to x-ray diffraction, pure B2O3 was confirmed to have BO3 triangles which formed the so-called boroxol ring structure. When Cs2O was added to B2O3, the boroxol ring structure still remained but some parts of BO3 triangles was definitely converted to BO4 tetrahedra. This result was also supported by Raman spectroscopic observations. The other important consequences were that a Cs atom was surrounded by six O atoms, and four Cs–O interatomic distances were about 3 Å but two pairs 3.5 Å, indicating that the distorted Cs–O octahedra might exist in the B2O3–Cs2O glasses. This spatial arrangement of Cs and O atoms was quite different from the corresponding crystal structure in the standpoint of the enormous decrease in coordination number (the number of O atoms around a Cs atom).