Structural and luminescent properties of Eu3+ doped Gd17.33(BO3)4(B2O5)2O16

Abstract

Crystal structure of gadolinium borate Gd_17.33(BO₃)₄(B₂O₅)₂O₁₆ has been refined by the Rietveld method from X-ray powder diffraction data. Gd_17.33(BO₃)₄(B₂O₅)₂O₁₆ crystallizes in the monoclinic space group Cm with lattice constants a=1841.70(3), b=374.08(1), c=1419.30(3) pm and β=119.85(1)°. The structure contains two types of borate groups BO₃^3– and B₂O₅^4– , and nine independent gadolinium atoms. IR, Raman and HREM studies supported the presence of these two different borate groups in the structure. The luminescent spectra of the Eu³⁺ doped material consist of several sharp lines originating from the optical transitions within the f⁶ configuration of the Eu³⁺ ions at different cation sites.