Syntheses, structure, and characterization of crystal La6Ba4(SiO4)6F2, a promising laser host

La6Ba4(SiO4)(6)F-2 crystals have been obtained from a BaF2-NaF flux system and a melt system. The compound crystallizes in the hexagonal system, space group P6(3)/m, with a = 9.8000(10) Angstrom, c = 7.3193-(8) Angstrom. and one formula unit per cell. La6Ba4(SiO4)(6)F-2 has an apatite structure, and all available evidence indicates that both the 6h and 4f lattice sites are occupied by La3+ and Ba2+ together. The absorption spectrum, emission spectrum, and fluorescence lifetime of the Yb3+-doped La6Ba4(SiO4)(6)F-2 crystal were also detected, and the wide and high emission band indicates that the crystal is a promising host for generation of ultra-short-pulse and tunable solid-state lasers.