Research On The Syntheses,Structures And Properties Of Lead Borate Halides And Mixed Alkali Borate Compound

This thesis was divided into three parts.In the first part,the explorations of PbO-H₃BO₃-PbX₂?X = F,Cl,Br?ternary systems were carried out,respectively.And a series of crystals were grown by high temperature solution method in the PbO-H₃BO₃-PbX₂?X = F,Cl,Br?system;in the second part,the synthesis,crystal structure,chemical and physical properties of a new lead-containing oxyborate bromine,[?O₂Pb₃?₂?BO₃?]Br,were carried out;in the last part,the syntheses,crystal structure and chemical and physical properties of a new mixed alkali borate,K₃CsB₂₀O₃₂,were also carried out.1.The PbO-H₃BO₃-PbX₂?X = F,Cl,Br?ternary systems were researched by adjusting the ratio of PbO,H₃BO₃ and PbX₂?X = F,Cl,Br?.A series of crystals were grown by high temperature solution method in the PbO-H₃BO₃-PbX₂?X = F,Cl,Br?systems.Among them,a new lead-containing oxyborate bromine,[?O₂Pb₃?₂?BO₃?]Br was obtained for the first time.2.[?O₂Pb₃?₂?BO₃?]Br crystallizes in the space group Cmcm?No.63?of the orthorhombic system with the following unit cell dimensions: a = 9.5748?8??,b = 20.841?2??,c = 5.7696?5??,and Z = 4.In the structure of [?O₂Pb₃?₂?BO₃?]Br,the OPb₄ tetrahedra and BO₃ groups can be seen as the basic building units.The OPb₄ oxocentered tetrahedra are interconnected through edges to form one-dimensional ?¹[O₂Pb₃] double chains,which are further connected to BO₃ groups,thus giving rise to the two-dimensional ?²[?O₂Pb₃?₂?BO₃?] layers,whereas the Br atoms are attached on the two sides of the adjacent ?²[?O₂Pb₃?₂?BO₃?] layers to form the three dimensional net structure of [?O₂Pb₃?₂?BO₃?]Br.Finally,the pure phase powder of [?O₂Pb₃?₂?BO₃?]Br was synthesized by high temperature solid state reaction,and the research of optical and thermal properties was carried out.3.A new mixed alkali borate was grown by high temperature solution method for the first time.K₃CsB₂₀O₃₂ crystallizes in the space group Pbca?No.61?of the orthorhombic system with the following unit cell dimensions: a = 7.5090?10??,b = 11.8078?16??,c = 14.775?2??,and Z = 2.The crystal structure of K₃CsB₂₀O₃₂ can be described as that B₅O₁₀ groups are connected to form the three-dimensional framework structure ?³[B₅O₈] of K₃CsB₂₀O₃₂ along b axis.And K/Cs atoms situated in the enclosed tunnels to form the whole structure of K₃CsB₂₀O₃₂.Finally,the pure phase powder of K₃CsB₂₀O₃₂ was synthesized by high temperature solid state reaction in order to carry out the research on the optical and thermal properties.