I want to ask about how to get the accurate valence statr of Cr in solution form? As from XPS I found it is +3 but somebody ask that Cr+3 can not be attached on material in acidic solution. So ask to do UV test for this confirmation.Now my question is how to check and confirm Cr +3 in solution form using UV vis.? Could you help me to find answer? Thanking you in anticipation.