Lead(II) chromate

Lead(II) chromate
Names
	Other names see text
Identifiers
CAS Number	7758-97-6 ;
ChEBI	CHEBI:86257 ;
ECHA InfoCard	100.028.951
EC Number	231-846-0;
PubChem CID	24460;
RTECS number	GB2975000;
UN number	3288
CompTox Dashboard (EPA)	DTXSID1064792 ;
Properties
Chemical formula	PbCrO4
Molar mass	323.192 g/mol
Appearance	orange-yellow powder
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
Magnetic susceptibility (χ)	−-18.0·10−6 cm3/mol
Refractive index (nD)	2.31
Structure
Crystal structure	monoclinic
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Carcinogen and highly toxic
	GHS labelling:
Pictograms	class="wikitable collapsible" style="min-width: 50em;"

See also

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Signal word

| Danger

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Hazard statements

| H350, H360, H373, H410

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Precautionary statements

| P201, P273, P308+P313, P501

|- | NFPA 704 (fire diamond)

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| colspan=2 style="text-align:left; background-color:#eaeaea;" | Lethal dose or concentration (LD, LC): |-

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LD₅₀ (median dose)

| >12 g/kg (mouse, oral)

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| Safety data sheet (SDS) | ICSC 0003
Sigma-Aldrich |-

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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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Infobox references

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Lead(II) chromate (Pb Cr O₄) is a chemical compound, a chromate of lead. It has a vivid yellow color and is insoluble in water, and as a result, is used in paints under the name chrome yellow.

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.

Structure

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.^[2]

Applications

Approximately 37,000 tons were produced in 1996. The main applications are as a pigment in paints.^[3] It has also been used in the paint to color school buses.

Lead chromate is used in some pyrotechnic compositions, especially delay compositions, as an oxidizer.^{[citation needed]}

Preparation

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.^[3]

Lead(II) chromate, historical dye collection of the Technical University of Dresden, Germany

Reactions

Heating in hydroxide solution produces chrome red, a red or orange powder made by PbO and CrO₃. Also, in hydroxide solution lead chromate slowly dissolves forming plumbite complex.

PbCrO₄ + 4 OH⁻ → [Pb(OH)₄]²⁻ + CrO₄²⁻

Safety hazards

Containing both lead and hexavalent chromium, lead chromate is treated with great care in its manufacture, the main concerns being dust. "extensive epidemiological investigations have given no indication that the practically insoluble lead chromate pigments have any carcinogenic properties".^[3]

In the 1800s, the product was used to impart a bright yellow color to some types of candy.^[4]

Previously, its use was more widespread. Lead(II) chromate and "white lead", or lead(II) carbonate, were the most common lead-based paint pigments.

References

^ ^a ^b ^c "Globally Harmonized System of Classification and Labelling of Chemicals" (pdf). 2021. Annex 3: Codification of Statements and Pictograms (pp 268–385).
^ 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
^ ^a ^b ^c Völz, Hans G. et al. "Pigments, Inorganic" in Ullmann's Encyclopedia of Industrial Chemistry, 2006 Wiley-VCH, Weinheim. 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)

[GHS2021_annex-3-1] "Globally Harmonized System of Classification and Labelling of Chemicals" (pdf). 2021. Annex 3: Codification of Statements and Pictograms (pp 268–385).

[2] 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

[Ullmann-3] Völz, Hans G. et al. "Pigments, Inorganic" in Ullmann's Encyclopedia of Industrial Chemistry, 2006 Wiley-VCH, Weinheim. doi:10.1002/14356007.a20_243.pub2.

[4] Wisconsin. State Board of Health (1887). Progress Report of Public Health in Wisconsin, Volume 10. p. 92. Retrieved 17 July 2013. (Google Books)

[1]

[2]

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Names


Other names see text
Identifiers
CAS Number	7758-97-6^Y
ChEBI	CHEBI:86257^N
ECHA InfoCard	100.028.951
EC Number	231-846-0
PubChem CID	24460
RTECS number	GB2975000
UN number	3288
CompTox Dashboard (EPA)	DTXSID1064792
Properties
Chemical formula	PbCrO₄
Molar mass	323.192 g/mol
Appearance	orange-yellow powder
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
Magnetic susceptibility (χ)	−-18.0·10⁻⁶ cm³/mol
Refractive index (n_D)	2.31
Structure
Crystal structure	monoclinic
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Carcinogen and highly toxic
GHS labelling:
Pictograms	class="wikitable collapsible" style="min-width: 50em;"
Pictogram	Code	Symbol description	Image link
	GHS01	{{GHS exploding bomb}}	Image:GHS-pictogram-explos.svg	Explosive
	GHS02	{{GHS flame}}	Image:GHS-pictogram-flamme.svg
	GHS03	{{GHS flame over circle}}	Image:GHS-pictogram-rondflam.svg
	GHS04	{{GHS gas cylinder}}	Image:GHS-pictogram-bottle.svg
	GHS05	{{GHS corrosion}}	Image:GHS-pictogram-acid.svg	Corrosive
	GHS06	{{GHS skull and crossbones}}	Image:GHS-pictogram-skull.svg	Accute Toxic
	GHS07	{{GHS exclamation mark}}	Image:GHS-pictogram-exclam.svg	Irritant
	GHS08	{{GHS health hazard}}	Image:GHS-pictogram-silhouette.svg	Health Hazard
	GHS09	{{GHS environment}}	Image:GHS-pictogram-pollu.svg	Environment

Code	Symbol description	Image link
GHS01	{{GHS exploding bomb}}	Image:GHS-pictogram-explos.svg	Explosive
GHS02	{{GHS flame}}	Image:GHS-pictogram-flamme.svg
GHS03	{{GHS flame over circle}}	Image:GHS-pictogram-rondflam.svg
GHS04	{{GHS gas cylinder}}	Image:GHS-pictogram-bottle.svg
GHS05	{{GHS corrosion}}	Image:GHS-pictogram-acid.svg	Corrosive
GHS06	{{GHS skull and crossbones}}	Image:GHS-pictogram-skull.svg	Accute Toxic
GHS07	{{GHS exclamation mark}}	Image:GHS-pictogram-exclam.svg	Irritant
GHS08	{{GHS health hazard}}	Image:GHS-pictogram-silhouette.svg	Health Hazard
GHS09	{{GHS environment}}	Image:GHS-pictogram-pollu.svg	Environment

Code	Symbol description	Image link
GHS01	{{GHS exploding bomb}}	Image:GHS-pictogram-explos.svg	Explosive
GHS02	{{GHS flame}}	Image:GHS-pictogram-flamme.svg
GHS03	{{GHS flame over circle}}	Image:GHS-pictogram-rondflam.svg
GHS04	{{GHS gas cylinder}}	Image:GHS-pictogram-bottle.svg
GHS05	{{GHS corrosion}}	Image:GHS-pictogram-acid.svg	Corrosive
GHS06	{{GHS skull and crossbones}}	Image:GHS-pictogram-skull.svg	Accute Toxic
GHS07	{{GHS exclamation mark}}	Image:GHS-pictogram-exclam.svg	Irritant
GHS08	{{GHS health hazard}}	Image:GHS-pictogram-silhouette.svg	Health Hazard
GHS09	{{GHS environment}}	Image:GHS-pictogram-pollu.svg	Environment

v t e Lead compounds
Pb(II)	Pb(BiO₃)₂ PbBr₂ Pb(C₅H₅)₂ Pb(C₂H₃O₂)₂ PbC₂O₄ PbCl₂ Pb(ClO₄)₂ PbCO₃ PbCrO₄ PbF₂ PbHAsO₄ PbI₂ Pb(C ₁₁H ₂₃COO) ₂ Pb(NO₃)₂ Pb(N₃)₂ PbO Pb(OH)₂ PbPo PbP₇ Pb₃(PO₄)₂ PbS Pb(SCN)₂ PbSe PbSO₄ PbSeO₄ PbTe PbTiO₃ PbGeO₃ C ₃₆H ₇₀PbO ₄ plumbite PbC₂ (hypothetical)
Pb(II,IV)	Pb₃O₄
Pb(IV)	Pb(C₂H₃O₂)₄ PbCl₄ PbF₄ PbH₄ PbO₂ PbS₂ plumbate Pb(OH)₄ (hypothetical)