Two layered galloborates from centric to acentric structures: syntheses and NLO properties

Abstract

Two layered galloborates (GBOs), Na₃GaB₄O₉ (1) and Na₅Ga[B₇O₁₂(OH)]₂·2B(OH)₃ (2), have been solvothermally made. 1 exhibits an unprecedented layer built by GaO₄ tetrahedra and B₄O₉ clusters. 2 was made by raising the ratio of B/Ga and the reaction temperature of 1, featuring a 2D acentric layer built by GaO₄ groups and B₇O₁₃(OH) clusters. 2 shows the highest second-harmonic generation (SHG) response of 4.6 times that of KDP (KH₂PO₄) among main group metal borates (MBOs).