β-BaGa[B4O8(OH)](H2O) and Ba4Ga[B10O18(OH)5](H2O): new barium galloborates featuring unusual [B4O8(OH)]5− and [B10O18(OH)5]11− clusters†
Abstract
Two new barium galloborates, namely, β-BaGa[B4O8(OH)](H2O) (1) and Ba4Ga[B10O18(OH)5](H2O) (2), have been synthesized by hydrothermal reactions. Compounds 1 crystallizes in centrosymmetric space group P![[1 with combining macron]](https://www.rsc.org/images/entities/char_0031_0304.gif)
and displays two-dimensional (2D) anionic layers composed of [B4O8(OH)]5− clusters and [Ga2O8]10− dimers interconnected by B–O–Ga linkages, furthermore Ba2+ ions and water molecules are located at the interlayer space. The neighbouring galloborate layers are connected via hydrogen bonds of water molecules. Compound 2 crystallizes in a polar space group Cc. In the structure, [B10O18(OH)5]11− clusters and [GaO4]5− tetrahedra are connected with each other to form a 3D network filled by Ba2+ ions and water molecules which consist of 1D tunnels based on unusual Ga3B16 19-member rings (MRs). The water molecules are coordinated with the Ba2+ ions and also form hydrogen bonds with the galloborate network. Second harmonic generation (SHG) measurements indicate that compound 2 displays a weak SHG response of about 0.2 times that of KH2PO4 (KDP). Optical properties, ferroelectric properties, piezoelectric properties, thermal stability and theoretical calculations based on density functional theory (DFT) methods of both compounds have also been studied.
 and Ba4Ga[B10O18(OH)5](H2O): new barium galloborates featuring unusual [B4O8(OH)]5− and [B10O18(OH)5]11− clusters](/en/Image/Get?imageInfo.ImageType=GA&imageInfo.ImageIdentifier.ManuscriptID=C4RA06564F&imageInfo.ImageIdentifier.Year=2014)
Please wait while we load your content...
