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用θ-2θ型X射线衍射仪研究了25℃Li_2SO_4·20H_2O溶液的结构.用经验公式r_(x-y)=0.618λ/sinθ进行溶液衍射曲线I-θ定性结构的分析,而用另一经验公式r_(x-y)=7.766/s计算加权结构函数曲线s·i(s)-s上某些强峰的原子间距.结构模型的精修研究表明,溶液中占优势的物种是四水合锂离子和八水合硫酸根离子.四面体水合锂离子Li-H_2O距离为0.20nm,配位数为4.四个顶点上水分子间距为0.321nm,相互作用数目为6.锂离子与第二配位层的水分子距离大约为0.425nm,配位数为12.水合硫酸根离子S-W距离为0.386nm,配位数为8.用对称模型描述了水合硫酸根离子中氧原子与水分子的四种相互作用,O_s-W(1),O_s-W(2),O_s-W(3)和O_s-W(4)距离分别精修为0.288nm,0.316nm,0.396nm和0,469nm.由于锂离子散射能力低,没有足够的证据表明溶液中存在接触离子对和溶剂共享离子对.
The structure of Li_2SO_4 · 20H_2O solution at 25 ℃ was investigated by θ-2θ X-ray diffractometer.The I-θ qualitative structure of the solution diffraction curve was analyzed by empirical formula r_ (xy) = 0.618λ / sinθ, and another empirical formula r_ (xy) = 7.766 / s Calculate the atomic spacing of some strong peaks in the weighted structure function curve s · i (s) -s. The refinement of the structural model shows that the predominant species in the solution are lithium ion tetrahydrate and Octahydrate hydrate.The tetrahedral hydrated lithium ion Li-H_2O has a distance of 0.20 nm and a coordination number of 4. The distance between the water molecules at the four vertices is 0.321 nm and the number of interactions is 6. The lithium ion and the second coordination layer Has a water molecule distance of about 0.425 nm and a coordination number of 12. The SW distance of the hydrated sulfate ion is 0.386 nm and the coordination number is 8. Using the symmetric model, four kinds of mutual interactions of oxygen atoms and water molecules in hydrated sulfate ions The distances between O_s-W (1), O_s-W (2), O_s-W (3) and O_s-W (4) were refined to 0.288nm, 0.316nm, 0.396nm and 0,469nm, respectively. Low capacity, there is not enough evidence to show that there is contact ion pairs and solvent shared ion pairs in solution.