Product name Medium Chrome Yellow,C.I.number:pigment yellow 34 CAS NO:1344-32-7 MF:PbCrO4 Product Characteristics: Chrome Yellow is a natural yellow pigment made of lead(II) chromateBecause the pigment tends to oxidize and darken on exposure to air over time,and it contains lead, a toxic, heavy metal, it has been largely replaced by another pigment, Cadmium Yellow (mixed with enough Cadmium Orang to produce a color equivalent to chrome yellow).