A terbium rich orthoborate LiSrTb2(BO3)3 and its analogues

A terbium rich orthoborate, LiSrTb2(BO3)(3), has been successfully synthesized by a solid state reaction and crystallized from a high temperature flux. Single crystal X-ray diffraction results show that LiSrTb2(BO3)(3) possesses the P (3) over bar m1 space group, with cell parameters of a = 10.3845(4) angstrom, c = 6.4739(8) angstrom, and Z = 3. In the structure, the terbium atom coordinates to eight oxygen atoms to yield a TbO8 polyhedron. These polyhedra are connected with each other to form a layer of trigonal [Tb3O21] and hexagonal [Tb6O33] blocks in the ab plane, and then the layers are further linked by the triangular BO3 groups along the c direction. The magnetic susceptibility measurements show that LiSrTb2(BO3)(3) exhibits paramagnetic behaviors from 2 K to 300 K. The diffuse optical reflection spectrum indicates that LiSrTb2(BO3)(3) is transparent in the range 500-1500 nm, and effective green emission is detected in the photoluminescence of LiSrTb2(BO3)(3). In addition, a series of isostructural lanthanide analogues LiSrLn(2)(BO3)(3) (Ln = Pr, Nd, Sm-Lu) and LiBaLn(2)(BO3)(3) (Ln = Pr, Nd, Sm-Tm) have also been prepared by solid state reactions.