| For the complexity of the aluminum hydrolyzing-polymerization process and only a few of the structure of the product are known,therefore, the evolution rule of polyaluminum morphology has yet been reached an agreement. Obtained pure polyaluminum compounds and solve their crystal structures is the best way to study the formation and evolution process of polyaluminum species as much as possible,In polyaluminum compounds system, the solubility of polyaluminum chloride to poly aluminum iodide increase in turn. So the polyaluminum iodide is conducive to the preparation of single crystal and study structure of polyaluminum better.This article explore 75℃ polyaluminum iodide phase diagram firstly, the drawing of polyaluminum iodide phase diagram at 75℃ is the first time, through continuous experiment, Al(OH)2(H2O)2I and [Al4(OH)6(H2O)12][Al(H2O)6]2I12 do exist in the phase diagram of 75℃, we have difficulty in choosing a certain substances dissolved polyaluminum iodide and measuring the concentration of aluminum ions accurately. We have tried several ways, such as, first alkali dissolve sample then acid, direct nitric acid to dissolve sample, 1+1HNO3 dissolve sample,1+3HNO3 dissolve sample, 1+5HNO3 dissolve sample, 1+15HNO3,10 mol/L NaOH digestion or adding water to dissolve directly there is still no solution to this problem,it is need to further change method for determination of the concentration of aluminum ions.In the process of drawing phase diagram, preparing a new kind of polyaluminum iodide — crystal of [Al4(OH)6(H2O)12][Al(H2O)6]2I12, it was characterized by single crystal structure analysis and describe. This unique structure is similar with bromide system of our group, found in the iodide system again, showing the stability of structure and the universality of polyaluminum. For the study of formation and evolution rule of polyaluminum species law has important significance.This article using the NaOH to adjust alkalization degree method, forcing hydrolysis of polyaluminum shape, a new crystal was prepared successfully. It has enriched the polyaluminum compound form, for further research in the form of polyaluminum providing important support. |
