Preparation and characterization of rare earth orthoborates, LnBO 3 (Ln = Tb, La, Pr, Nd, Sm, Eu, Gd, Dy, Y) and LaBO 3:Gd, Tb, Eu by metathesis reaction: ESR of LaBO 3:Gd and luminescence of LaBO 3:Tb, Eu

Abstract

Lanthanide orthoborates of composition LnBO 3 (Ln = Tb, La, Pr, Nd, Sm, Eu, Gd, Dy, Y) and LaBO 3:Gd, Tb, Eu have been prepared by metathesis reaction. This method provides a convenient route for the synthesis of orthoborates and its solid solutions at low temperatures. Powder X-ray diffraction and FT-IR spectroscopy were used to characterize these borates. Rare earth borates, (LnBO 3) are isomorphous with different forms of CaCO 3 depending on the radius of rare earth ion. LaBO 3, LaBO 3:Gd, Tb, Eu, PrBO 3, NdBO 3 crystallized in aragonite structure, SmBO 3 crystallized in H-form and TbBO 3, EuBO 3, GdBO 3, DyBO 3, YBO 3 crystallized in vaterite structure. The structural analysis of TbBO 3 was carried out. The morphology of these borates was obtained from Scanning electron microscopy. Spin-Hamiltonian parameters for Gd 3+ are deduced from room temperature electron spin resonance spectrum of LaBO 3:Gd. The luminescence of LaBO 3:Tb, Eu gave characteristics peaks corresponding to Tb 3+, Eu 3+ respectively.