Synthesis And Structure Characterization Of Pb₂O[BO₂（OH）],LibaB₉O₁5 Crystals

Metal borates are of current interest because of their rich structural chemistry and some of them have special properties. Such as diverse applications in luminous, mineralogy, catalysis, ion exchange, and nonlinear-optical（NLO） materials. In the borate caystals, the boron atoms are hybridized forming sp2 structure with trigonal symmetry [BO₃] or sp³ structure exhibiting tetrahedral symmetry [BO4]. These [BO₃] triangle and [BO4] tetrahedra can be connected via common corners oxygen atoms to form rigid boron-oxygen groups and then form a variety of degrees of polymerization like 0- dimensional island, one- dimensional ring、chain,two-dimensional layer and three- dimensional framework anions.Therefore,B-O groups and a lot of cations bond formation a variety of borates structures.One new metal oxyborate Pb₂O[BO₂（OH）] have been synthesized by using hydrothermal method. The crystallography data are collected by X-ray single crystal diffractometer, the SHELX-97 software is used to resolve the single cryatal structure. All of the compounds have been charactized by PXRD,IR,TG/DSC, EDS,UV-vis-NIR diffuse reflectance spectra.A new lead borate constructed of different cluster building units of isolated BO₃ and one- dimensional [OPb₄] chain is obtained as two-dimensional layer,The 2D layers are linked together via strong hydrogen bonds leading to the evolution of a 3D crystal lattice. Pb₂O[BO₂（OH）] crystallizes in the centrosymmetric monoclinic space group C2/m（No.12）,with a = 12.725（7） ?, b = 5.698（3） ?, c = 7.344（4） ?, β = 116.277（6）° V=477.5（4）?³,Z=4. The 1D chains comprise solely of Pb2+-O2- bonds in which the μ4-oxide ion sits in the center of a distorted tetrahedron in which four Pb2+ ions occupy the apical positions, that is anion-centered OPb₄ tetrahedra in Pb₂O[BO₂（OH）] structure.The 1D chains are further connected through orthoborate（HBO₃）2- ligands, bridging two Pb2+ from two different {Pb2O}2+ chains, thus giving rise to two-dimensional（2D） layers. The 2D layers are linked together via hydrogen bonds leading to the evolution of a 3D crystal lattice.In the PbO-B₂O₃ systems, lead-containing OPb₄ tetrahedra borate Pb₂O[BO₂（OH）] have been synthesized by hydrothermal, not only enrich the structure type of borates,but also explore metal borate materials with a certain value and significance.One kind of alkali（earth） metal borate LiBaB₉O₁5 was sysnthesised by hydrothermal reactions. Singal-crystal X-ray diffraction analysis, XRD, IR also determined the crystal structure. LiBaB₉O₁5 crystalized in space group R3 c,the crystal data was a= 10.970（10） ?,c=17.044（2） ?, V=1777.0（3） ?³. The crystal structure including B₃O₇ ring, Li and Ba are located in the center of the B-O large ring,to form a three-dimensional network structure.