Dermatotoxicological aspects of metallic chromium

Figure 1. A quantum chemical model of the charge distribution of Cr⁰ (A), Cr³⁺ (B), and Cr⁶⁺ (C). The electrostatic potential is mapped on an ab initio calculated electron density surface (electron density on the surface is similar in each picture showing overall size of the 3 compounds). The colour indicates the electrostatic potential on the surface, red indicating the highest negative charge and blue, the highest positive charge. Calculations and graphics by Olli Aitio, M.Sc (Department of Pharmaceutical Chemistry, University of Helsinki) using SPARTAN software (Version 4.0 Wavefunction, Inc., Irvine California).

Figure 2. Chromate salts are common causes of allergic contact dermatitis. The figure illustrates allergic patch test reactions elicited by both trivalent chromate (CrCl₃) and hexavalent chromate (K₂Cr₂O₇) (courtesy R. Jolanki).