Synthesis and Characterization of H-LnBO3 Orthoborates (Ln=La, Nd, Sm, and Eu)

Depending on the ionic radius of the rare earth ions, orthoborates exhibit three different crystalline forms noted LnBO3 and H-LnBO3. A comparative study of the stability relationship of H-LnBO3 borate (Ln=La, Nd, Sm, and Eu) versus the temperature and synthesis method (solid state reaction and wet process) is reported. These high temperature forms have been characterized by X-ray diffraction, high temperature X-ray diffraction, and IR spectroscopy. This work was completed by a study of luminescence properties of H-LaBO3 orthoborate doped by Eu3+.