Liesegang patterns of silver dichromate (Ag₂Cr₂O₇) are studied in two different gel media: agar and gelatin, based on the work of Lagzi and Ueyama Chem. Phys. Lett.2009, 468, 188-192. Whereas in gelatin, standard Liesegang bands are obtained as a result of the interdiffusion of Ag⁺ and ${\text{Cr}}_2{\text{O}}_7^{2-}$, random crystallites with dendritic ramifications are observed in agar. We revisit this phenomenon and demonstrate the proposed mechanism, wherein dense heterogeneous nucleation in gelatin leads to Liesegang bands, as opposed to surface nucleation in agar yielding crystallites. We use viscosity, pH measurements, and notably scanning electron microscopy (SEM) in this endeavor.

根据Lagzi和Ueyama Chem的工作，在两种不同的凝胶介质（琼脂和明胶）中研究了重铬酸银（Ag ₂ Cr ₂ O ₇）的Liesegang模式。物理 来吧 2009年，468，188-192。而在明胶中，由于Ag ⁺和${\text{铬}}_{\mathrm{2个}}{\text{Ø}}_7^{\mathrm{2个}--}$，在琼脂中观察到具有树枝状分枝的无规微晶。我们重新审视这种现象并证明了所提出的机理，其中明胶中的致密异质成核导致Liesegang带，与琼脂产生微晶的表面成核相反。在此过程中，我们使用粘度，pH值测量，尤其是扫描电子显微镜（SEM）。