Kanimian Tamar, Nasr Pamela, Sultan Rabih
Department of Chemistry, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut 1107 2020, Lebanon.
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-0001, United States.
ACS Omega. 2024 Oct 18;9(43):43635-43641. doi: 10.1021/acsomega.4c05735. eCollection 2024 Oct 29.
Liesegang patterns present a display of parallel stripes of precipitate that arise from the interdiffusion of coprecipitate ions in a gel medium. The bands observed in rocks are typical analogies of this phenomenon, and their composition is not restricted to the banded deposition of a single mineral. We here extend the study to a three-precipitate system, wherein Co, Ni, and Cd cations are precipitated by the same anion (OH from NHOH) to form Co(OH), Ni(OH), and Cd(OH), respectively. The resulting pattern exhibits an alternation of compact mixed Co(OH) and Ni(OH) bands with granules of pure Cd(OH) between them. The obtained pattern confirms the generic type of ( + )//( + )//( + )/ alternation conjectured analytically using the competitive particle growth (CPG) model and stability analysis.
李泽冈环纹呈现出沉淀的平行条纹，这是由共沉淀离子在凝胶介质中的相互扩散产生的。在岩石中观察到的条带是这种现象的典型类似物，并且它们的组成不限于单一矿物的条带状沉积。我们在此将研究扩展到一种三沉淀体系，其中钴、镍和镉阳离子由同一阴离子（来自氢氧化铵的氢氧根）沉淀，分别形成氢氧化钴、氢氧化镍和氢氧化镉。所得图案呈现出紧密混合的氢氧化钴和氢氧化镍条带与其间纯氢氧化镉颗粒的交替。所获得的图案证实了使用竞争粒子生长（CPG）模型和稳定性分析进行解析推测的（ + ）//（ + ）//（ + ）/交替的一般类型。
