Crystal Structure of SrAl2B2O7 and Eu2+ Luminescence

The crystal structure of strontium dialuminodiborate SrAl2B2O7 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) Å and c=47.78(1) Å. Aluminium and boron atoms are, respectively, in tetrahedral and triangular oxygen coordination. The assembly of Al2O7 units and BO3 triangles forms double layers between which Sr2+ ions are located. The Eu2+-doped crystalline powder exhibits a luminescence band with maximum at 415 nm. Luminescence characteristics are compared to those of other strontium borates.