A warm yellow pigment made from lead chromate. Dutch painter Vincent van Gogh used chrome yellow in many of his paintings, including in his famous series of sunflower still lifes. Because chrome yellow tends to oxidize and darken over time, and it contains lead (a toxic heavy metal), it has been largely replaced by other pigments. Web resource here. Video here.

Vincent van Gogh. Vase with Twelve Sunflowers. Oil on canvas. 1889. Philadelphia Museum of Art.