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本文用X射线和差热分析方法对BaO-Li2O-B2O3三元系中的两个截面:BaB2O4-Li2B2O4和BaB2O4-Li2O作了研究。在BaB2O4-Li2B2O4赝二元系中发现了一个新的化合物4BaB2O4·Li2B2O4。化合物在930±3℃由包晶反应形成,并与Li2B2O4形成共晶反应。共晶温度为797±3℃,共晶点组分为79mol％Li2B2O4。在BaB2O4-Li2O截面中也存在化合物4BaB2O4·Li2B2O4,其包晶反应温度从930±3℃随Li2O含量增加下降到908±3℃。在组分60mol％Li2O处形成另一个新的化合物2BaB2O4·3Li2O。该化合物在630±3℃也是由包晶反应形成,并与Li2O和Li2CO3分别形成共晶反应,共晶温度分别为400±3℃和612±3℃。在BaB2O4-Li2B2O4和BaB2O4-Li2O体系中都没有观察到固溶体。用计算机程序分别对化合物4BaB2O4·Li2B2O4和2BaB2O4·3Li2O的X射线粉末衍射图案进行了指标化,其结果:4BaB2O4·Li2B2O4的空间群为Pmma,a=13.033?,b=14.630?,c=4.247?,每个单胞包含两个化合式单位;2BaB2O4·3Li2O的空间群为Pmmm,a=4.814?,b=9.897?,c=11.523?,每个单胞也含有两个化合式单位。The pseudo-binary systems BaB2O4-Li2B2O4 and BaB2O4-Li2O in ternay system BaO-Li2O-B2O3 have been studied by means of X-ray diffraction and thermal -analysis. A new compound 4BaB2O4 ·Li2B2O4 which is formed by peritectic reaction at 930 ± 3℃ has been discovered in the BaB2O4-Li2B2O4 system. There is a eutectic horizontal from 4BaB2O4 ·Li2B2O4 to Li2B2O4 at 797±3℃ with a eutectic point component of 79 mol% Li2B2O4. In BaB2O4-Li2O system, there also exists a compound of 4BaB2O4 ·Li2B2O4, formed by peritectic reaction. But its peritectic reaction temperature dropped to 908±3℃ with increasing amount of Li2O. Another new compound 2BaB2O4 ·3Li2O is formed by peritectic reaction at 630±3℃ and eutectic reaction occur from 2BaB2O4 ·3Li2O to Li2O at 400±3℃ and from 2BaB2O4 ·3Li2O to Li2CO3 at 612±3℃. No solid solution is observed in BaB2O4-Li2B2O4 and BaB2O4-Li2O systems.The X-ray powder diffraction pattens of 4BaB2O4 ·Li2B2O4 and 2BaB2O4 ·3Li2O have been indexed by computed programme. It is shown that the space group of 4BaB2O4·Li2B2O4 is Pmma with lattice parameters α = 13.033?, b=14.630?, c = 4.247?. There are two formula units per unit cell. The space group of 2BaB2O4 ·3Li2O is Pmmm. Lattice parameters are α = 4.814?, b = 9.897?, c=11.523?. There are two formula units per unit cell.
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