|Molar mass||323.2 g/mol|
|Density||6.12 g/cm3, solid|
|Melting point||844 °C (1,551 °F; 1,117 K)|
|Solubility in water||negligible|
|Solubility||soluble in diluted nitric acid
insoluble in acetic acid, ammonia
|Refractive index (nD)||2.31|
|EU classification||Carc. Cat. 2
Repr. Cat. 1/3
Dangerous for the environment (N)
|R-phrases||R45, R61, R33, R62, R50/53|
|S-phrases||S53, S45, S60, S61|
|LD50||>12 g/kg (mouse, oral)|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Lead(II) chromate (PbCrO4) is a chemical compound, a chromate of lead. It has a vivid yellow color and is practically insoluble in water, and as a result, is used in paints under the name chrome yellow. It is commonly made in the laboratory by reacting a lead(II) salt (such as lead(II) nitrate) with a chromate or dichromate salt (such as potassium chromate or potassium dichromate) in solution in water, producing a very deep yellow to orange precipitate of lead(II) chromate.
Lead(II) chromate may also be known as chrome yellow, chromic acid lead(II) salt, canary chrome yellow 40-2250, chrome green, chrome green UC61, chrome green UC74, chrome green UC76, chrome lemon, crocoite, dianichi chrome yellow G, lemon yellow, king's yellow, Leipzig yellow, lemon yellow, Paris yellow, pigment green 15, plumbous chromate, pure lemon chrome L3GS, and various other names. The mineral crocoite, occurring as orange-yellow prismatic crystals, is a moderately rare mineral known from the oxidation zones of such Pb ore beds, that were affected by chromate-bearing solutions, coming from the oxidation of primary Cr minerals (chromite) of the nearby (ultra)mafic rocks.
Lead(II) chromate is used in some pyrotechnic compositions, especially delay compositions, as an oxidizer. Up to the late 1800s it was used to impart a bright yellow color to some types of candy. It has also been used in the paint to color school buses.(Chrome Yellow)
- PbCrO4 + 4 OH− → [Pb(OH)4]2- + CrO42-
Lead(II) chromate is a poison, and can be fatal if swallowed or inhaled.
Lead(II) chromate is a known carcinogen, developmental toxicant, and reproductive toxicant. It is also suspected that lead(II) chromate is a cardivascular or blood toxicant, immunotoxicant, kidney toxicant, neurotoxicant, respiratory toxicant, and a skin toxicant or sense organ toxicant.
If swallowed, lead(II) chromate poisoning can lead to abdominal pain and spasms, nausea, vomiting, and headaches. If the poisoning is not severe, one may experience lead line on the gums, a metallic taste, muscle weakness, and dizziness. The symptoms appear to get worse as the poisoning becomes more severe. Severe poisoning can lead to a coma and even death.
If inhaled, and the poisoning is not severe, one may experience symptoms such as a sore throat, coughing, shortness of breath, and labored breathing. Severe poisoning may lead to pulmonary edema, as well as several symptoms experienced from indigestion.
- Wisconsin. State Board of Health (1887). Progress Report of Public Health in Wisconsin, Volume 10. p. 92. Retrieved 17 July 2013. (Google Books)