CompTox Dashboard (EPA)
|Molar mass||323.192 g/mol|
|Density||6.12 g/cm3, solid|
|Melting point||844 °C (1,551 °F; 1,117 K)|
|Solubility||soluble in diluted nitric acid |
insoluble in acetic acid, ammonia
Refractive index (nD)
|Main hazards||Carcinogen and highly toxic|
|Safety data sheet||ICSC 0003|
|GHS signal word||Danger|
|H350, H360, H373, H410|
|P201, P273, P308+313, P501|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|>12 g/kg (mouse, oral)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Lead(II) chromate may also be known as chrome yellow, chromic acid lead(II) salt, canary chrome yellow 40-2250, Holtint Middle Chrome, 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 chromate adopts the monazite structure, meaning that the connectivity of the atoms is very similar to other compounds of the type MM'O4. Pb(II) has a distorted coordination sphere being surrounded by eight oxides with Pb-O distances ranging from 2.53 to 2.80 Å. The chromate anion is tetrahedral, as usual.
Approximately 37,000 tons were produced in 1996. The main applications are as a pigment in paints. It has also been used in the paint to color school buses.
Lead(II) chromate can be produced by treating sodium chromate with lead salts such as lead(II) nitrate or by combining lead(II) oxide with chromic acid. Related pigments are produced by the addition of sulfate, resulting in a mixed lead-chromate-sulfate compositions, the so-called lead sulfochromate.
- PbCrO4 + 4 OH− → [Pb(OH)4]2− + CrO42−
Containing both lead and hexavalent chromium, lead chromate is treated with great care in its manufacture, the main concerns being dust. "[E]xtensive epidemiological investigations have given no indication that the practically insoluble lead chromate pigments have any carcinogenic properties".
In the 1800s, the product was used to impart a bright yellow color to some types of candy. It is used (illegally) to enhance the color of certain spices, particularly turmeric, particularly in low income countries such as Bangladesh.
- Quareni, S.; de Pieri, R. "A three-dimensional refinement of the structure of crocoite, PbCrO4" Acta Crystallographica 1965, volume 19, p287-p289. doi:10.1107/S0365110X65003304
- Völz, Hans G.; et al. (2006). "Pigments, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a20_243.pub2..
- Wisconsin. State Board of Health (1887). Progress Report of Public Health in Wisconsin, Volume 10. p. 92. Retrieved 17 July 2013. (Google Books)
- "The American Spice Trade Association's Statement on Lead in Turmeric - ASTA: The Voice of the U.S. Spice Industry in the Global Market". ASTA: The Voice of the U.S. Spice Industry in the Global Market. 28 October 2013. Retrieved 21 November 2018.
- Angelon-Gaetz, Kim A.; Klaus, Christen; Chaudhry, Ezan A.; Bean, Deidre K. (23 November 2018). "Lead in Spices, Herbal Remedies, and Ceremonial Powders Sampled from Home Investigations for Children with Elevated Blood Lead Levels — North Carolina, 2011–2018". MMWR. Morbidity and Mortality Weekly Report. 67 (46): 1290–1294. doi:10.15585/mmwr.mm6746a2. ISSN 0149-2195. PMC 6289082. PMID 30462630.
- "Researchers find lead in turmeric". Phys. Stanford University. 24 September 2019. Retrieved 1 October 2019.
- Forsyth, Jenna E.; Nurunnahar, Syeda; Islam, Sheikh Shariful; Baker, Musa; Yeasmin, Dalia; Islam, M. Saiful; Rahman, Mahbubur; Fendorf, Scott; Ardoin, Nicole M.; Winch, Peter J.; Luby, Stephen P. (December 2019). "Turmeric means "yellow" in Bengali: Lead chromate pigments added to turmeric threaten public health across Bangladesh". Environmental Research. 179: 108722. doi:10.1016/j.envres.2019.108722.