How does electron confinement in an ion or molecule affect its color?

Why do different ions and oxidation states of the same ions have different colors in solutions? Do you know of any examples and web sites?
Tyah (juliette59@hotmail.com)

The more electrons are confined, the closer the spacings between their energy levels and so the bluer the colors they absorb. Different ions obviously confine their electrons differently, and so have different colors.

Check out the Water to Wine article on this site. It shows how acid-base indicator color changes are caused by changes in electron confinement. You'll find links on the bottom of the article to several relevant sites (some with Java applets that let you see how electron confinement affects color).

Author: Fred Senese senese@antoine.frostburg.edu

Copyright © 1997-2010 by Fred Senese
Comments & questions to fsenese@frostburg.edu
Last Revised 02/23/18.URL: http://antoine.frostburg.edu/chem/senese/101/quantum/faq/electron-confinement-and-color.shtml