Al8(BO3)4(B2O5)F8: A F-Containing Aluminum Borate Featuring Two Types of Isolated B-O Groups.

Al8(BO3)4(B2O5)F8, as a new aluminum borate fluoride, has been synthesized by the high-temperature reaction with the closed system for the first time. With respect to its structure, the isolated BO3 and B2O5 groups reside in the center and edge of tunnels constructed by the AlO4F2 polyhedra. The AlO4F2 polyhedra play the vital role on the formation of isolated B-O groups. According to our investigation, Al8(BO3)4(B2O5)F8 is the first case, which features two types of independently isolated B-O groups in the aluminum borate fluorides. Its cutoff edge is up to deep ultraviolet (DUV) range. What is more, the energy dispersive spectroscopy (EDS), infrared (IR) spectrum, and the first-principles calculations of Al8(BO3)4(B2O5)F8 have been performed.