通过氧化汞(HgO)在氢碘酸(HI)溶液中反应实验,研究了HgO-HI-H2O生长体系中反应物浓度的变化对最终Hg I2结晶形貌的影响。采用岛津UV-2550紫外可见分光光度计分析了反应体系中离子及配合物的种类;采用LEICA-DM2500P偏光显微镜观察了结晶物质的的宏观生长形貌;利用盒计数法定量表征了Hg I2结晶物在衬底表面的覆盖度。结果表明,体系中存在[Hg I3]-和[Hg I4]2-两种配合物;随着生长体系浓度(Hg I2析出速率)的变化,Hg I2出现了两种结晶形貌。分析认为,高溶质浓度体系容易形成四方形晶粒,生长形貌主要受晶体结构因素影响;低浓度体系容易形成密枝晶,其形貌主要受分子扩散动力学因素控制。
Mercuric iodide crystal was obtained by solvent evaporation in Hg O-HI-H2O reaction system at room temperature. The influence of solution concentrations on HgI2 crystal morphology was investigated.Hg-I complexes in system were determined by visible and UV spectrometer; the macroscopic morphology of crystals was observed using a LEICA-DM2500 P polarizing microscope; the fraction dimension of HgI2 crystal was estimated via the modified box-counting method. The results indicate that complexes [HgI3]-and [HgI4]2-were identified in the solution. It tend to form tetragonal HgI2 grain in high concentration system and its crystallizing morphology is controlled by crystal structure of HgI2; nevertheless,dense branch morphology( DBM) mainly exists in low one and its morphology controlled by " diffusion limited aggregation"( DLA) model.