Growth, structure, and properties of single crystals of SrBPO5

Single crystals of strontium borophosphate, SrBPO5, have been grown with sizes up to 25 x 15 x 10 mm(3) from the BPO4 flux by the top-seeded solution growth method. The compound crystallizes in the trigonal system, space group P3(2)21 (No. 154), with a = 6.8850(10) Angstrom, c = 6.8700(14) Angstrom, and three formula units per cell. The SrBPO5 compound is built up of infinite anionic units of BO4 and PO4 tetrahedra joined by common vertexes. It contains single chains of BO4 tetrahedra running parallel to [001], which are linked to terminal PO4 tetrahedra to form spiral chains. The ultraviolet transmission spectrum of SrBPO5 crystals was reported. The refractive indices were measured by the minimum deviation technique and fitted to the Sellmeier equations. The crystal exhibits an optical second-harmonic generation effect similar to that of KDP (KH2PO4).