Turkish Journal of Physics

Abstract: Boro-phosphate glasses containing transition metal oxides are of special interest. Hence, some sodium-Boro-phosphate glasses containing iron and antimony oxides were prepared and investigated. The structural investigation indicated the presence of different borate groups as well as tetragonal phosphate units. Most of the iron cations were found to occupy the low spin Fe^{3 +} in the tetrahedral coordination state. It was observed that some antimony act as network former cations and some others act as bridges between any two adjacent polyhedra. At high antimony oxide content, the formation of some Sb-Fe bonds was also detected. The magnetic susceptibility measurements showed a maximum value when antimony oxide reached 15 mol %, but decreased with higher concentration. Between 20 mol % and 30 mol %, the magnetic susceptibility exhibited approximately stable value, indicating that at 15 mol % of antimony oxide content, most iron cations occupy the tetrahedral coordination state. The observed decrease in the magnetic susceptibility at higher concentrations may be due to the formation of some Sb-Fe bonds, which act to pair the iron d-electrons, in addition to the increase of Sb₂O₃ content which has low magnetic properties. The obtained density and the calculated molar volume values showed approximately linear increase. The increase of the density can be attributed to the differences in the molecular weights of both boron and antimony oxides, while the increase of the molar volume can be ascribed to the radius and the volume effects of the increasing antimony cations.

Key Words: Glass structure, Physical properties of glass, Glass containing antimony and iron oxides