White Chromium II metal complexes in open change in colour ______?

White chromium(II) complexes in open air will change color from white to blue, green, or pink as they are oxidized to other chromium states like \(Cr^{3+}\) or \(Cr^{6+}\). The exact color change depends on the other ligands in the complex and the specific oxidation state achieved, with different chromium oxidation states and ligands resulting in a range of colors, from the familiar green of \(Cr(H_{2}O)_{6}^{3+}\) to the yellow of chromate ions.