New nonlinear optical crystal: NaBa4Al2B8O18Cl3

Single crystals of NaBa(4)Al(2)B(8)O(18)Cl(3) have been grown with sizes up to 34 × 34 × 16 mm(3) from the NaF-LiCl flux by the top-seeded solution growth method. The compound crystallizes in the tetragonal system, space group P4(2)nm, with a = 12.0480 (16) ?, c = 6.8165 (11) ?, α = β = γ = 90°, and two formula units per cell. The NaBa(4)Al(2)B(8)O(18)Cl(3) compound is built up of infinite anionic groups of AlB(4)O(12)](9-) formed by two BO(4) tetrahedra, one AlO(4) tetrahedra, and two BO(3) triangles. Optical properties including ultraviolet transmission, IR spectrum, and second-harmonic generation of NaBa(4)Al(2)B(8)O(18)Cl(3) crystals were reported. Refractive indices were measured by the minimum deviation technique and fitted to the Sellmeier equations. Thermal properties such as the DSC and thermal expansion were reported. The mechanical properties including the hardness, density, and chemical stability were also reported.