Chrome yellow

Chrome yellow is lead(II) chromate (PbCrO₄). It occurs naturally as the mineral crocoite but the mineral itself was never used as a pigment in paintings. After the French chemist Louis Vauquelin discovered the new element chromium in 1797 lead chromate has been synthesized in the laboratory and its use as a pigment started in the second decade of the nineteenth century.

Because the pigment tends to oxidize and darken on exposure to air over time, and it contains lead, a toxic, heavy metal, it was originally replaced by another pigment, cadmium yellow (mixed with enough cadmium orange to produce a color equivalent to chrome yellow).

Chrome yellow had been commonly produced by mixing solutions of lead nitrate and potassium chromate and filtering off the lead chromate precipitate.

The first recorded use of chrome yellow as a color name in English was in 1818.

The Piper J-3 Cub aircraft had chrome yellow as its standard overall color, usually called "Cub Yellow" or "Lock Haven Yellow" in aviation circles, from the Piper factory that existed in Lock Haven, Pennsylvania, where it was made in the 1930s and during World War II.

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