Crystalline and water soluble Cr(4+) and Cr(5+) model compounds for chromium toxicity studies

We discuss two complexes of Cr( 4+) for their possible utility as models for Cr toxicity studies. They are Cr( dien)( O-2) (2) . H2O ( dien = diethylenetriamine) and Cr(NH3)(3)(O-2)(2), which have been recently characterized by x- ray diffraction and magnetic techniques. We present their optical and infrared absorption spectra as quick aids in their identification procedure. We also summarize the general properties of some well- characterized Cr( 5+) compounds. All of these compounds are water soluble with the Cr( 5+) samples being fairly stable in basic solutions. They can all be prepared as pure crystals with a shelf life of over 2 years when stored in a refrigerator.