K5Mg2La3(BO3)6: An Efficient, Deep-Ultraviolet Nonlinear Optical Material

KBe2BO3F2 (KBBF) is the sole nonlinear optical (NLO) crystal that can practically generate deep-ultraviolet (UV) coherent light by a direct second-harmonic generation (SHG) process. However, the toxic BeO and crystal layer habit limit its application. With this background, a new beryllium-free borate, K5Mg2La3(BO3)(6 )(KMLBO), has been designed and synthesized through a high-temperature solution method. KMLBO crystallizes into the noncentrosymmetric space group P31m (No. 157) and features a three-dimensional framework structure consisting of alveolate [LaBO3](infinity) layers further tightly bound via interlayer [BO3](3-) groups. KMLBO not only exhibits desirable performances including deep-UV transparency, large SHG (similar to 3.1 XKH2PO4), and phase-matchability but also overcomes the crystal layer habit of KBBF, demonstrating that it is a potential deep-UV NLO crystal.

Automated summary

KBBF is the only NLO crystal that can generate deep-UV light through SHG, but its toxic nature and crystal structure limitations have led to the design and synthesis of KMLBO, a beryllium-free borate with potential deep-UV NLO crystal applications. KMLBO exhibits promising performances and overcomes the crystal layer habit of KBBF, making it a potential candidate for deep-UV NLO crystals.