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{{Unreferenced|date=December 2009}} {{Use dmy dates|date=September 2020}}
{{Chembox {{Chembox
| Watchedfields = changed
| verifiedrevid = 300365492 | verifiedrevid = 448015777
| Name = Zinc chromate | Name = Zinc chromate
| ImageFileL1 =Zn2+.svg
| ImageFile =
| ImageSizeL1 = 35px
| ImageFileR1 =Chromat-Ion2.svg
| ImageFile2 = Zinc-chromate-3D-vdW.png
| IUPACName = Zinc chromate | IUPACName = Zinc chromate
| OtherNames = | OtherNames =
| SystematicName =
| Section1 = {{Chembox Identifiers | Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite}} | CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 13530-65-9 | CASNo = 13530-65-9
| ChemSpiderID = 24301
| EINECS = 236-878-9
| PubChem = 26089 | PubChem = 26089
| RTECS = GB3290000 | RTECS = GB3290000
| UNNumber = 3288 3077
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 05F2837HUF
}} }}
| Section2 = {{Chembox Properties | Section2 = {{Chembox Properties
| Formula = ZnCrO<sub>4</sub> | Formula = ZnCrO<sub>4</sub>
| MolarMass = 181.403 g/mol | MolarMass = 181.403 g/mol
| Appearance = yellow-green crystals | Appearance = yellow-green crystals; yellow&nbsp;powder
| Density = 3.43 g/cm<sup>3</sup> | Density = 3.43 g/cm<sup>3</sup>
| MeltingPt = 316 °C | MeltingPtC = 316
| BoilingPt = 732 °C | BoilingPtC = 732
| Solubility = insoluble | Solubility = insoluble
}} }}
Line 24: Line 34:
| CrystalStruct = | CrystalStruct =
}} }}
| Section4 =
| Section5 =
| Section6 =
| Section7 = {{Chembox Hazards | Section7 = {{Chembox Hazards
| GHS_ref=
| EUClass = not listed
| GHSPictograms = {{GHS07}}{{GHS08}}{{GHS09}}
⚫ | NFPA-H =
| NFPA-F = | GHSSignalWord = Danger
| HPhrases = {{H-phrases|302|317|350|410}}
⚫ | NFPA-R =
| PPhrases = {{P-phrases|201|202|261|264|270|272|273|280|281|301+312|302+352|308+313|330|333+313|363|391|405|501}}
⚫ | NFPA-O =
⚫ | NFPA-H = 2
⚫ | NFPA-F = 0
⚫ | NFPA-R = 0
| NFPA-S = OX
| PEL = 0.1 mg/m<sup>3</sup><ref name="OHSAChemSample"/>
| LD50 = 0.5 to 5 g/kg
}} }}
| Section8 = {{Chembox Related
| OtherAnions = Zinc dichromate
| OtherCations = ]<br/>]
}}
}} }}
⚫ ] bombers, painted with Zinc Chromate undercoat, being assembled, 1942]]
'''Zinc chromate''', ]]], is a ] containing the ] ]. It is used industrially in ]s.


'''Zinc chromate''', ]]], is a ], a salt containing the ] ], appearing as odorless yellow powder or yellow-green crystals, but, when used for coatings, pigments are often added.<ref name="CameoC">{{Cite web |title= ZINC CHROMATE - CAMEO Chemicals |author= National Oceanic and Atmospheric Administration |author-link= National Oceanic and Atmospheric Administration |url=http://cameochemicals.noaa.gov/chemical/9194|access-date=24 March 2011}}</ref><ref name="OHSAGuideline">{{Cite web |title= OHSA Guideline for Zinc Chromate |publisher= ] |url= http://www.osha.gov/SLTC/healthguidelines/zincchromate/recognition.html |access-date=24 March 2011}}</ref><ref name="Pohanish2004">{{cite book|author=Richard P. Pohanish|title=HazMat data: for first response, transportation, storage, and security|url=https://books.google.com/books?id=3Tbl2W8j-3oC&pg=PA1155|year=2004|publisher=John Wiley and Sons|isbn=978-0-471-27328-8|page=1155}}</ref> It is used industrially in ]s, having been developed by the ] in the 1920s.<ref name="Waligorski">{{Cite web |title=Everything You Need to Know About Zinc Chromate |first=Martin |last=Waligorski |url=http://www.colorserver.net/history/history-zinc-chromate.htm |access-date=23 March 2011}}</ref>
Its use as a corrosion resistant agent was applied to ] alloy parts first in commercial aircraft, and then in military ones. During the 1940 and 1950s it was typically found as the "paint" in the wheel wells of retractable landing gear on U.S. military aircraft, not because of its glaring yellow-green color symbolizing anything, but to protect the aluminium from corrosion.


==Production==
When used as a pigment, it is known as Zinc Yellow or Yellow 36. It is highly toxic and rarely used in art anymore.


A process known as the ] is used to create zinc chromate for use in industry. This process is done by putting zinc or a zinc plated metal in a solution of ] and ] for a few seconds.<ref name="innovateus">{{Cite web|title=What is Zinc Chromate Used For|publisher=innovateus |url=http://www.innovateus.net/science/what-zinc-chromate-used |access-date= 11 December 2014}}</ref> Zinc chromate can also be synthesized by using neutral potassium chromate (K<sub>2</sub>CrO<sub>4</sub>) and zinc sulfate (ZnSO<sub>4</sub>), which forms a precipitate.<ref>{{cite book|title=Paint and Coating Testing Manual|date=1995|publisher=American Society for Testing and Aircraft Materials|location=Philadelphia, PA|page=241}}</ref>
⚫ {{Zinc compounds}}


K<sub>2</sub>CrO<sub>4</sub> + ZnSO<sub>4</sub> → ZnCrO<sub>4</sub> + K<sub>2</sub>SO<sub>4</sub>
⚫ {{DEFAULTSORT:Zinc Chromate}}
<gallery>
⚫ ]
File:Zinkchromat.jpg|zinc chromate (powder)
⚫ ]
⚫ File:Alfred T. Palmer - Assembling the North American B-25 Mitchell at Kansas City, Kansas (USA).jpg|] bombers, painted with zinc chromate undercoat, being assembled, 1942
</gallery>


==Uses==


Zinc chromate's main use is in industrial painting as a coating over iron or aluminium materials.<ref name="ReferenceA">{{cite journal|last1=Tencer|first1=Michal|title=Electrical conductivity of chromate conversion coating on electrodeposited zinc|journal=Applied Surface Science|date=30 September 2006|volume=252|issue=23|pages=8229–8234|doi=10.1016/j.apsusc.2005.10.039|bibcode=2006ApSS..252.8229T}}</ref> It was used extensively on aircraft by the US military, especially during the 1930s and 1940s. It is also used in a variety of paint coatings for the aerospace and automotive industries.<ref>{{cite journal|last1=Hall|first1=A.F.|title=Occupational contact dermatitis among aircraft workers|journal=American Journal of Medicine|date=1944|volume=125}}</ref> Its use as a corrosion-resistant agent was applied to ] alloy parts first in commercial aircraft, and then in military ones. During the 1940 and 1950s it was typically found as the "paint" in the wheel wells of retractable landing gear on US military aircraft to protect the aluminium from corrosion. This compound was a useful coating because it is an anti-corrosive and anti-rust primer.<ref name="ReferenceA"/> Since it is highly toxic, it also destroys organic growth on the surface. Zinc chromate is also used in spray paints, artists' paints, pigments in varnishes, and in making linoleum.<ref name="Waligorski"/>
{{Inorganic-compound-stub}}


When used as a pigment, it is known as Zinc Yellow,<ref name="CameoC"/> Buttercup Yellow or Yellow 36.<ref name="CLand21">{{Cite web |title=Basic Zinc Chromate |publisher=Chemical Land21 |url=http://www.chemicalland21.com/industrialchem/IUH/BASIC%20ZINC%20CHROMATE.htm |access-date= 24 March 2011}}</ref> It is rarely used in art because the pigment degenerates into a brown color. This effect can be seen in Georges Seurat's famous painting '']''.<ref>{{cite book|first=John |last=Gage|title=Color and Culture: Practice and Meaning from Antiquity to Abstraction|url=https://archive.org/details/colorcultureprac00gage |url-access=limited |location=Boston|publisher=Little, Brown|year=1993|pages= , 224|isbn=9780821220436}}.</ref> The degradation of zinc yellow in Seurat's painting was thoroughly investigated<ref>{{cite journal | last1 = Casadio | first1 = F. | last2 = Xie | first2 = S. | last3 = Rukes | first3 = S. C. | last4 = Myers | first4 = B. | last5 = Gray | first5 = K. A. | last6 = Warta | first6 = R. | last7 = Fiedler | first7 = I. | year = 2011| title = Electron energy loss spectroscopy elucidates the elusive darkening of zinc potassium chromate in Georges Seurat's A Sunday on La Grande Jatte–1884 | journal = Analytical and Bioanalytical Chemistry | volume = 399 | issue = 9| pages = 2909–20 | doi = 10.1007/s00216-010-4264-9 | pmid = 20953774 | s2cid = 26844464 }}</ref> and these findings were subsequently employed in a digital rejuvenation<ref>, ColourLex</ref> of the painting.<ref>{{cite journal |last1=Berns |first1=R. S. |last2=Byrns |first2=S. |last3=Casadio |first3=F. |author-link3=Francesca Casadio |last4=Fiedler |first4=I. |last5=Gallagher |first5=C. |last6=Imai |first6=F. H. |last7=Taplin |first7=L. A. |year=2006 |title=Rejuvenating the color palette of Georges Seurat's A Sunday on La Grande Jatte—1884: A simulation |journal=Color Research & Application |volume=31 |issue=4 |pages=278–293 |doi=10.1002/col.20223}}</ref><ref>, ColourLex</ref>
]

]
Zinc chromate putty was used as sealant in addition to two ] between sections of the failed ] on ]. Blowholes in this putty may have been a minor contributor to ].<ref name="Hickman1997">{{cite book|author=J.A. Hickman|title=Polymeric Seals and Sealing Technology|url=https://books.google.com/books?id=mOZ-97d6KmsC&pg=PA25|year=1997|publisher=iSmithers Rapra Publishing|isbn=978-1-85957-096-8|page=25}}</ref>
]

]
==Toxicity==

Recent studies have shown that not only is zinc chromate highly toxic, it is also a ] because it contains ].<ref>{{cite journal|last1=Holmes|first1=A.L.|title=Chronic exposure to zinc chromate induces centrosome amplification and spindle assembly checkpoint bypass in human lung fibroblasts|journal=Chemical Research in Toxicology|date=15 February 2011|volume=23|issue=2|pages=386–395|doi=10.1021/tx900360w|pmc=2822114|pmid=20030412}}</ref> Exposure to zinc chromate can cause tissue ulceration and cancer.<ref name="OHSAChemSample">{{Cite web |title= OHSA Chemical Sampling Information for Zinc Chromate |publisher= ] |url= http://www.osha.gov/dts/chemicalsampling/data/CH_276900.html |access-date=24 March 2011}}</ref><ref name="OHSAGuideline"/> A study published in the ''British Journal of Industrial Medicine'' showed a significant correlation between the use of zinc chromate and lead chromate in factories and the number of cases in lung cancer experienced by the workers.<ref>{{cite journal|last1=Davies|first1=J.M.|title=Lung cancer mortality among workers making lead chromate and zinc chromate pigments at three English factories|journal=British Journal of Industrial Medicine|date=May 1984|volume=41|issue=2|pages=158–169|pmc=1009277|pmid=6722042|doi=10.1136/oem.41.2.158}}</ref> Because of its toxicity the use of zinc chromate has greatly diminished in recent years.{{cn|date=February 2024}}

==References==
{{Reflist}}

⚫ {{Zinc compounds}}
{{Chromates and dichromates}}

⚫ {{DEFAULTSORT:Zinc Chromate}}
⚫ ]
⚫ ]

Latest revision as of 13:17, 17 June 2024

Zinc chromate
Names
IUPAC name Zinc chromate
Identifiers
CAS Number
ChemSpider
ECHA InfoCard 100.033.511 Edit this at Wikidata
EC Number
  • 236-878-9
PubChem CID
RTECS number
  • GB3290000
UNII
UN number 3288 3077
CompTox Dashboard (EPA)
Properties
Chemical formula ZnCrO4
Molar mass 181.403 g/mol
Appearance yellow-green crystals; yellow powder
Density 3.43 g/cm
Melting point 316 °C (601 °F; 589 K)
Boiling point 732 °C (1,350 °F; 1,005 K)
Solubility in water insoluble
Hazards
GHS labelling:
Pictograms GHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Signal word Danger
Hazard statements H302, H317, H350, H410
Precautionary statements P201, P202, P261, P264, P270, P272, P273, P280, P281, P301+P312, P302+P352, P308+P313, P330, P333+P313, P363, P391, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
2 0 0OX
Lethal dose or concentration (LD, LC):
LD50 (median dose) 0.5 to 5 g/kg
NIOSH (US health exposure limits):
PEL (Permissible) 0.1 mg/m
Related compounds
Other anions Zinc dichromate
Other cations Potassium chromate
Sodium chromate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). checkY verify (what is  ?) Infobox references
Chemical compound

Zinc chromate, ZnCrO4, is a chemical compound, a salt containing the chromate anion, appearing as odorless yellow powder or yellow-green crystals, but, when used for coatings, pigments are often added. It is used industrially in chromate conversion coatings, having been developed by the Ford Motor Company in the 1920s.

Production

A process known as the Cronak process is used to create zinc chromate for use in industry. This process is done by putting zinc or a zinc plated metal in a solution of sodium dichromate and sulfuric acid for a few seconds. Zinc chromate can also be synthesized by using neutral potassium chromate (K2CrO4) and zinc sulfate (ZnSO4), which forms a precipitate.

K2CrO4 + ZnSO4 → ZnCrO4 + K2SO4

  • zinc chromate (powder) zinc chromate (powder)
  • B-25 Mitchell bombers, painted with zinc chromate undercoat, being assembled, 1942 B-25 Mitchell bombers, painted with zinc chromate undercoat, being assembled, 1942

Uses

Zinc chromate's main use is in industrial painting as a coating over iron or aluminium materials. It was used extensively on aircraft by the US military, especially during the 1930s and 1940s. It is also used in a variety of paint coatings for the aerospace and automotive industries. Its use as a corrosion-resistant agent was applied to aluminium alloy parts first in commercial aircraft, and then in military ones. During the 1940 and 1950s it was typically found as the "paint" in the wheel wells of retractable landing gear on US military aircraft to protect the aluminium from corrosion. This compound was a useful coating because it is an anti-corrosive and anti-rust primer. Since it is highly toxic, it also destroys organic growth on the surface. Zinc chromate is also used in spray paints, artists' paints, pigments in varnishes, and in making linoleum.

When used as a pigment, it is known as Zinc Yellow, Buttercup Yellow or Yellow 36. It is rarely used in art because the pigment degenerates into a brown color. This effect can be seen in Georges Seurat's famous painting A Sunday Afternoon on the Island of La Grande Jatte. The degradation of zinc yellow in Seurat's painting was thoroughly investigated and these findings were subsequently employed in a digital rejuvenation of the painting.

Zinc chromate putty was used as sealant in addition to two O-rings between sections of the failed solid rocket booster on Space Shuttle Challenger. Blowholes in this putty may have been a minor contributor to its catastrophic loss.

Toxicity

Recent studies have shown that not only is zinc chromate highly toxic, it is also a carcinogen because it contains Cr(VI). Exposure to zinc chromate can cause tissue ulceration and cancer. A study published in the British Journal of Industrial Medicine showed a significant correlation between the use of zinc chromate and lead chromate in factories and the number of cases in lung cancer experienced by the workers. Because of its toxicity the use of zinc chromate has greatly diminished in recent years.

References

  1. ^ "OHSA Chemical Sampling Information for Zinc Chromate". Occupational Safety and Health Administration. Retrieved 24 March 2011.
  2. ^ National Oceanic and Atmospheric Administration. "ZINC CHROMATE - CAMEO Chemicals". Retrieved 24 March 2011.
  3. ^ "OHSA Guideline for Zinc Chromate". Occupational Safety and Health Administration. Retrieved 24 March 2011.
  4. Richard P. Pohanish (2004). HazMat data: for first response, transportation, storage, and security. John Wiley and Sons. p. 1155. ISBN 978-0-471-27328-8.
  5. ^ Waligorski, Martin. "Everything You Need to Know About Zinc Chromate". Retrieved 23 March 2011.
  6. "What is Zinc Chromate Used For". innovateus. Retrieved 11 December 2014.
  7. Paint and Coating Testing Manual. Philadelphia, PA: American Society for Testing and Aircraft Materials. 1995. p. 241.
  8. ^ Tencer, Michal (30 September 2006). "Electrical conductivity of chromate conversion coating on electrodeposited zinc". Applied Surface Science. 252 (23): 8229–8234. Bibcode:2006ApSS..252.8229T. doi:10.1016/j.apsusc.2005.10.039.
  9. Hall, A.F. (1944). "Occupational contact dermatitis among aircraft workers". American Journal of Medicine. 125.
  10. "Basic Zinc Chromate". Chemical Land21. Retrieved 24 March 2011.
  11. Gage, John (1993). Color and Culture: Practice and Meaning from Antiquity to Abstraction. Boston: Little, Brown. pp. 220, 224. ISBN 9780821220436..
  12. Casadio, F.; Xie, S.; Rukes, S. C.; Myers, B.; Gray, K. A.; Warta, R.; Fiedler, I. (2011). "Electron energy loss spectroscopy elucidates the elusive darkening of zinc potassium chromate in Georges Seurat's A Sunday on La Grande Jatte–1884". Analytical and Bioanalytical Chemistry. 399 (9): 2909–20. doi:10.1007/s00216-010-4264-9. PMID 20953774. S2CID 26844464.
  13. Digital restoration of paintings, ColourLex
  14. Berns, R. S.; Byrns, S.; Casadio, F.; Fiedler, I.; Gallagher, C.; Imai, F. H.; Taplin, L. A. (2006). "Rejuvenating the color palette of Georges Seurat's A Sunday on La Grande Jatte—1884: A simulation". Color Research & Application. 31 (4): 278–293. doi:10.1002/col.20223.
  15. Georges Seurat, A Sunday Afternoon on the Island of La Grande Jatte', ColourLex
  16. J.A. Hickman (1997). Polymeric Seals and Sealing Technology. iSmithers Rapra Publishing. p. 25. ISBN 978-1-85957-096-8.
  17. Holmes, A.L. (15 February 2011). "Chronic exposure to zinc chromate induces centrosome amplification and spindle assembly checkpoint bypass in human lung fibroblasts". Chemical Research in Toxicology. 23 (2): 386–395. doi:10.1021/tx900360w. PMC 2822114. PMID 20030412.
  18. Davies, J.M. (May 1984). "Lung cancer mortality among workers making lead chromate and zinc chromate pigments at three English factories". British Journal of Industrial Medicine. 41 (2): 158–169. doi:10.1136/oem.41.2.158. PMC 1009277. PMID 6722042.
Zinc compounds
Zinc(I)
Organozinc(I) compounds
Zinc(II)
Organozinc(II) compounds
  • Zn(CH3)2
  • Zn(C2H5)2
  • Zn(CH3COO)2
  • Zn(CH(CH3)2)2
  • Zn(C(CH3)3)2
  • Zn(C6H5)2
  • Zn(C3H5O3)2
  • ZnICH2I
    • Chromates and dichromates
    Chromates
    Chlorochromates
    Chromate esters
    Dichromates
    Related
    Categories: