In this open-ended activity, students design crystallizations to can see who can grow the biggest crystals of their colorful products. This addition is something that I add to the standard M(acac)3 syntheses that many of us do as an introductory lab in an upper level course or as a final lab in an introductory type course. Syntheses of the M(acac)3 starting materials are available in most published inorganic laboratory manuals.
- Szafran, Z.; Pike, R. M.; and Singh, M. M. Microscale Inorganic Chemistry: A Comprehensive Laboratory Experience; Wiley & Sons: New York, 1991, p. 224.
- Girolami, G.S.; Rauchfuss, T. B.; Angelici, R. J. Synthesis and Technique in Inorganic Chemistry: A Laboratory Manual, 3rd Ed.; University Science Books: Sausalito, CA, 1999, p. 117.
- Inorganic Experiments, 3rd Ed., Woollins, J. D., Ed.; Wiley/VCH: Weinheim, 2010, p. 109.
- Students will learn how to do solubility tests on inorganic compounds
- Students will learn how to recrystallize compounds using layering, vapor diffusion, and slow evaporation techniques (different from those they typically use in organic lab)
- Students will understand the concept of miscibility and how it relates to crystallization techniques
- Students will also learn that crystallization is a trial and error process and not every method results in the production of good crystals!
- M(acac)3 complexes such as those of Fe(III), Co(III), Cr(III), and Mn(III)
- Small glass scintillation vials, large capped glass jars for vapor diffusion
- A range of solvents of different polarities and densities: my version uses water, methanol, ethanol, acetone, acetonitrile, methylene chloride, ethyl ether, toluene, and pentane.
- Tables of miscibilities, densities, and polarities (available on the web and in catalogs such as the Sigma-Aldrich catalog, see weblinks below).