Ba3Ca4(BO3)3(SiO4)Cl: a new non-centrosymmetric complex alkaline-earth metal borosilicate chloride with a deep-ultraviolet cut-off edge†
A new complex alkaline-earth metal borosilicate chloride Ba3Ca4(BO3)3(SiO4)Cl has been successfully synthesized by the high-temperature solution method. It crystallizes in the space group P63mc (no. 186) of the hexagonal system. Its structure features a 3∞[Ca4(BO3)3(SiO4)] framework formed by interconnected 1∞[Ca4(BO3)3(SiO4)O9] chains with large octagonal star-like channels, in which the 1∞[Ba3Cl] chains are located. The second harmonic generation (SHG) measurement shows that Ba3Ca4(BO3)3(SiO4)Cl has an SHG of about 0.6 times that of KH2PO4 and it is phase matchable. In addition, it melts congruently and exhibits a wide transparent range with the UV cut-off edge below 190 nm. All the above indicates that Ba3Ca4(BO3)3(SiO4)Cl could be regarded as a potential ultraviolet nonlinear optical material.