BaCIBF₄: A new noncentrosymmetric pseudo-Aurivillius type material with transparency range from deep UV to middle IR and a high laser damage thresholdf

A new noncentrosymmetric alkaline earth metal ha I id e borate, BaClBF₄, has been synthesized with crystal size up to 6 mm × 6mm × 3 mm via the hydrothermal method at 200 °C. The crystal structure can be described as an alternate stacking of cationic [Ba₂CI₂]²⁺ layers with anionic [BF₄]^- layers along the b direction, and the [Ba₂CI₂]²⁺ layer is a pseudo-Aurivillius type layer similar to the [Bi₂O²]²⁺ layer. The transmittance range of BaClBF4 is from 0.18 to 8.5 |im, and the laser damage threshold of the crystal is about 6.8 GW cm^-2. EDS, TG-DSC and second harmonic generation investigations are reported. The electronic structure is discussed to explain the structure-property relationships.