Rhythmic Banding of Precipitates (Liesegang's Rings)

McGuigan, Hugh; Brough, G.A.

doi:10.1016/s0021-9258(18)85356-x

Cited by 8 publications

(3 citation statements)

References 13 publications

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“…The breathtaking beauty of Passion flower lies partly in the characteristic alternation of violet and white bands in each one of them as illustrated in Figure 1a. The observation of such concentric bands in chemical systems is reminiscent of Liesegang rings (McGuigan and Brough 1923;Stern 1954;Krug and Brandtstädter 1999) formed during the precipitation of silver dichromate from silver nitrate and potassium dichromate solutions in a gel. Bhatnagar and Sehgal had invoked the same mechanism for explaining the formation of rings in beet roots (Bhatnagar and Sehgal 1926).…”

Section: Introductionmentioning

confidence: 97%

Pattern formation in Passiflora incarnata: An activator-inhibitor model

et al. 2021

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Based on a careful examination of the onset of violet colored dots along the filaments in the developing floral bud stage and the formation of alternating bands of violet and white color in the matured flowers of Passiflora incarnata (Passion flower), it is concluded that the pattern arises from a competition between the production of violet colored anthocyanin and the colorless flavonols along the filaments. The activator-inhibitor model of Gierer and Meinhardt along with the reaction diffusion theory of Turing is used to explain the formation of concentric rings in the flower.

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Section: Introductionmentioning

confidence: 97%

Pattern formation in Passiflora incarnata: An activator-inhibitor model

et al. 2021

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“…Self-assembly and pattern formation are widespread phenomena in nature. − They are essential in biomineralization processes where templated growth and feedback mechanisms lead to the formation of mechanically robust skeletal structures. − Pattern formation is also observed in larger-scale geological systems. A well-known example of macroscopic pattern formation is the mineral banding in porous rocks referred to as Liesegang banding (after Liesegang) that is generally caused by reactions occurring after the formation of the host rock. − Such features have been interpreted as the result of coupling between chemical reactions and reactant transport in porous media. ,,,, Interpretations of Liesegang-type banding phenomena remain speculative, however, because of the lack of reproducible experimental systems that demonstrate how they are formed.…”

Section: Introductionmentioning

confidence: 99%

Emergent Behavior at the Calcite–Water Interface during Reactive Transport in a Simple Microfluidic Channel

Abdilla

Minahan

Gleghorn

et al. 2022

ACS Earth Space Chem.

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Geochemical reactive transport processes in natural mineral–fluid systems may produce a wide array of emergent phenomena that are difficult to predict from basic principles and to reproduce in model systems. Here, we present experimental results obtained from a simple microfluidic system with which we explored the consequences of reacting the calcite (104) cleavage surface with an acidic Pb-bearing solution (pH = 3.5, [Pb]total = 5 mM) as a function of flow rate. This system is relevant to passive remediation systems for Pb-rich acid mine drainage. We observed periodic banding in the amounts of Pb sorption at flow velocities ≥926 μm s–1, where the band spacing was spatially correlated with the amount of calcite dissolution and the development of micropyramidal topography on the calcite (104) surface. The equivalent coverage of Pb deposited in these Pb-rich bands was at least several monolayers per unit cell, yet there was no evidence for precipitation of any secondary Pb phase implying incorporation of Pb within the near-surface calcite lattice. We also observed spatial variations in nucleation and growth of euhedral secondary Pb-carbonate minerals hydrocerusite and cerussite at flow rates ≤278 μm s–1. These findings demonstrate potential for exploiting the rich phenomenology afforded by the interplay among transport phenomena and chemical kinetics in experimental systems designed to yield deeper insights into geochemical self-organization.

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“…Since their discovery in 1896, Liesegang patterns, with their unique and intriguing periodic structures, have attracted the attention of chemists, physicists, biologists, and geologists for more than a century, especially because they are ubiquitous in nature. The patterns can be formed by two oppositely charged ions precipitating when their concentrations exceed a threshold characterized by their solubility constant, resulting in patterns consisting of a variety of sparingly soluble inorganic salts such as hydroxide salts, − chromate and dichromate, − phosphates, , oxalate, and others. − The variety of pattern-formation processes offers a basis for developing a robust model to unlock the mysteries of biological Liesegang phenomena. − Furthermore, recent developments in microfabrication processes have made it possible to fabricate complicated microtemplates for functionally patterned Liesegang materials consisting of inorganic salts with the desired size, shape, and symmetry. , …”

Section: Introductionmentioning

confidence: 99%

Liesegang Patterns Engineered by a Chemical Reaction Assisted by Complex Formation

2014

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Liesegang rings based on a chemical reaction, not a conventional precipitation reaction, have been developed by appropriate design of the nucleation dynamics in a system involving complex formation in a matrix. The periodic and concentric rings consisted of well-dispersed Ag nanoparticles with diameters of a few nanometers. The approach modeled here could be applied to form novel micropatterns out of inorganic salts, metal nanoparticles, organic nanocrystals, or polymeric fibers, and it could also offer a scaffold for novel models of a wide variety of reaction-diffusion phenomena in nature.

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Rhythmic Banding of Precipitates (Liesegang's Rings)

Cited by 8 publications

References 13 publications

Pattern formation in Passiflora incarnata: An activator-inhibitor model

Pattern formation in Passiflora incarnata: An activator-inhibitor model

Emergent Behavior at the Calcite–Water Interface during Reactive Transport in a Simple Microfluidic Channel

Liesegang Patterns Engineered by a Chemical Reaction Assisted by Complex Formation

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