Crystal Structure of SrAl_2B_2O_7 and Eu~(2+) Luminescence

摘要

The crystal structure of strontium dialuminodiborate SrAl_2B_2O_7 has been established by single-crystal X-ray diffraction methods. The compound crystallizes in the trigonal system (space group R3c, Z=6) with cell parameters a=4.893(1) A and c=47.78(1) A. Aluminium and boron atoms are, respectively, in tetrahedral and triangular oxygen coordination. The assembly of Al_2O_7 units and BO_3 triangles forms double layers between which Sr~(2+) ions are located. The Eu~(2+) -doped crystalline powder exhibits a luminescence band with maximum at 415 nm. Luminescence characteristics are compared to those of other strontium borates.