Synthesis, structure and characterization of Pr[B5O8(OH)]NO3·2H2O

Abstract

A new rare earth metal borate crystalline compound Pr[B5O8(OH)]NO3·2H2O (1) containing nitrate anions was obtained using a hydrothermal method. The crystal structure was examined using single-crystal X-ray diffraction. The compound crystallises in the monoclinic system (space group P21/n) with a = 6.4619(5) Å, b = 15.4518(13) Å, c = 10.5754(8) Å, β = 90.357(2)° and V = 1055.91(14) Å3. The basic building block of the compound was a [B5O10(OH)]6− polyanion cluster, which forms a two-dimensional B–O layered structure; The Pr3+ ions fill the windows of the B–O layers, whereas the nitrates and water molecules occupy the gaps between the B–O layers. The crystal structure was further characterised using powder diffraction, infrared transmission spectroscopy and thermogravimetric analysis. In addition, the solid-state fluorescence emission spectra of the crystal were measured, showing the characteristic emission peaks of Pr3+.

Keywords

• Borate
• Pr
• Rare earth metal
• Crystal structure
• Fluorescence
• Nitrate