Resumen de Solvatochromism of Cupric Chloride and Its Conversion to Copper Oxide
Michael J. Jenkins, Miranda A. Phillips, Zi-Ling Xue
This experiment demonstrates that copper(II) chloride dihydrate (CuCl2·2H2O) in different solvents (acetone, isopropyl alcohol, or water) displays divergent colors and visible-near IR spectra. Both the reactions of these solutions with 2 equiv of sodium hydroxide (NaOH) and the direct solid-state reaction of CuCl2·2H2O with 2NaOH using a mortar and pestle give copper(II) oxide (CuO). Undergraduate students learn the following: (1) d–d electronic transitions in a transition metal complex; (2) effects of solvent polarity changes on the electronic ground and excited state of Cu2+ ions as well as color differences; (3) direct solid-state reaction as a green synthetic method; (4) gradual formation of CuO from solution reactions of CuCl2·2H2O with 2 equiv of NaOH; (5) characterization of chemical compounds in solutions by visible-near IR spectroscopy and solid products by IR and powder X-ray diffraction (PXRD). This experiment is suitable as a junior-level inorganic chemistry experiment.
