Synthesis and characterization of three new rare-earth orthoborates: Ba2MgY2(BO3)4, Ba2CdY2(BO3)4, and Ba2CdSc(BO3)3

Three rare-earth orthoborates Ba2MgY2(BO3)4, Ba2CdY2(BO3)4, and Ba2CdSc(BO3)3 were synthesized via a high-temperature solution method and their structures were determined by single crystal X-ray diffraction for the first time. Ba2MgY2(BO3)4 and Ba2CdY2(BO3)4 are isostructural and both crystallize in the monoclinic crystal system, P21/c, while Ba2CdSc(BO3)3 crystallizes in the triclinic crystal system, P. The structures of Ba2MgY2(BO3)4 and Ba2CdY2(BO3)4 can be described as the three-dimensional (3D) frameworks composed of MO5 (M = Mg, Cd), YOn (n = 6, 7) polyhedra with isolated BO3 and Ba2+ cations residing in the space of the frameworks. The structure of Ba2CdSc(BO3)3 is composed of 2D [CdSc(BO3)3]∞ layers separated by Ba2+ cations. In addition, structural comparisons, thermal behaviors, UV-vis-NIR diffuse reflectance spectra, and infrared spectroscopy results are also reported.