Collect. Czech. Chem. Commun. 2001, 66, 541-554

Crystal Selection and Liesegang Banding in Dynamic Precipitate Systems

Shoghag Panjarian and Rabih Sultan*

Department of Chemistry, American University of Beirut, Beirut, Lebanon


We report on some phenomenological properties of precipitate patterns grown in gels. The experiments span a variety of salt systems, and yield patterns ranging from Liesegang bands to exotic crystals and to a combination of both depending on the initial conditions. The obtained crystals encompass spots, crystallites and notably dendrites of fractal nature. The particle number and size observed in discrete spotted bands of a cobalt oxinate Liesegang pattern provide a direct verification of Ostwald ripening.

Keywords: Liesegang; Periodic precipitation; Crystal growth; Ostwald ripening; Dendrites; Lead fluoride; Lead iodide; Chromium fluoride; Cobalt oxinate.

References: 40 live references.