01675nam a22002777a 4500 20231116104537.0 231020b ||||| |||| 00| 0 eng d 0021-9584 RIEBPL Library 540.7 Simeen Sattar Quinacridone Red and Violet: An Infrared Surprise (Journal Article) USA :American Chemical Society August 2023 3044-3049 P. American Chemical Society, Volume 100, Issue 8 ***______{For Hard Copy, Please visit Library.}________*** Abstract Quinacridone red and violet are visually different colors, an observation confirmed by their visible reflectance spectra and CIE L*a*b* coordinates. However, their IR spectra are extremely similar. Though chemically identical, the two quinacridones are polymorphs. In this experiment, designed for and tested by nonscience majors, the pigments are extracted from oil paints with hexane in a short procedure involving sonification and centrifugation. ATR-FTIR spectra of the recovered brilliantly colored powders reveal the presence of a calcium carbonate filler in one of the two paints. Factoring out the carbonate bands, the spectra are nearly identical. Students must reconcile the evidence of color and the evidence of the spectra. Nonmajor Courses Laboratory Instruction Hands-On Learning/Manipulatives Applications of Chemistry Dyes/Pigments UV−Vis Spectroscopy IR Spectroscopy https://pubs.acs.org/doi/epdf/10.1021/acs.jchemed.3c00316 PER 0 0 0 0 RIEBPL RIEBPL 2023-11-16 0 540.7 2023-11-16 00:00:00 2023-11-16 PER 44884 44883