View source for Paris green

{{Short description|Highly toxic arsenic-based pigment}}
{{Use dmy dates|date=April 2023}}
{{for-multi|the 1920 American silent film|Paris Green (film)|the Boardwalk Empire episode|Paris Green (Boardwalk Empire)}}
{{redir|Mountain green|the place in Utah|Mountain Green, Utah}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 415295806
| ImageFile = Schweinfurter Grün.svg
| ImageSize = 300px
| IUPACName = 
| OtherNames = C.I. pigment green 21, emerald green, Schweinfurt green, imperial green, Vienna green, Mitis green, Veronese green<ref>{{cite web|url=http://www.tucsonaz.gov/arthazards/paint1.html |title=Health & Safety in the Arts -- Painting & Drawing Pigments |publisher=Environmental Management Division, City of Tucson AZ |access-date=2011-02-07 |url-status=dead |archive-url=https://web.archive.org/web/20110720114307/http://www.tucsonaz.gov/arthazards/paint1.html |archive-date=2011-07-20 }}</ref>
|Section1={{Chembox Identifiers
| InChI = 1S/2C2H4O2.6AsHO2.4Cu/c2*1-2(3)4;6*2-1-3;;;;/h2*1H3,(H,3,4);6*(H,2,3);;;;/q;;;;;;;;4*+2/p-8
| InChIKey = HTSABAUNNZLCMN-UHFFFAOYSA-F
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 12002-03-8
| ChemSpiderID = 17215797
| EINECS = 601-658-7
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = X4916E1P1M
| UNNumber = 1585
| PubChem = 22833492
| SMILES = CC(=O)[O-].CC(=O)[O-].[O-][As]=O.[O-][As]=O.[O-][As]=O.[O-][As]=O.[O-][As]=O.[O-][As]=O.[Cu+2].[Cu+2].[Cu+2].[Cu+2]
| SMILES1 = CC(=O)[O-].CC(=O)[O-].[O-][As]0O[As]([O-])O[As]([O-])O0.[O-][As]0O[As]([O-])O[As]([O-])O0.[Cu+2].[Cu+2].[Cu+2].[Cu+2] }}
|Section2={{Chembox Properties
| Formula = Cu(C<sub>2</sub>H<sub>3</sub>O<sub>2</sub>)<sub>2</sub>·3Cu(AsO<sub>2</sub>)<sub>2</sub>
| MolarMass = 1013.79444 g/mol
| Appearance = Emerald green crystalline powder 
| Density = >1.1 g/cm<sup>3</sup> (20&nbsp;°C)
| MeltingPt = >
| MeltingPtC =345
| BoilingPt = decomposes
| Solubility = insoluble
| SolubleOther = soluble but unstable in acids<br />insoluble in alcohol}}
|Section3={{Chembox Hazards
| ExternalSDS = [http://cameochemicals.noaa.gov/chemical/2981 CAMEO MSDS]
| GHSPictograms = {{GHS06}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|302|410}}
| PPhrases = {{P-phrases|260|264|273|280|301+312|301+330+331|303+361+353|362|304+340|310|305+351+338|391|405|501}}
| FlashPt = 
| AutoignitionPt = 
| LD50 = 22 mg/kg
| IDLH = Ca [5 mg/m<sup>3</sup> (as As)]<ref name=PGCH>{{PGCH|0038}}</ref>
| REL = Ca C 0.002 mg/m<sup>3</sup> [15-minute]<ref name=PGCH/>
| PEL = [1910.1018] TWA 0.010 mg/m<sup>3</sup><ref name=PGCH/>
 }}
}}
{{Infobox color
|title=Paris green
|hex=50C878
|source=Maerz and Paul<ref>The color displayed in the color box above matches the color called ''emerald green'' in the 1930 book by Maerz and Paul ''A Dictionary of Color'' New York:1930 [[McGraw-Hill]]; the color ''emerald green'' is displayed on page 75, Plate 26, Color Sample J10.</ref>
|isccname=Vivid yellowish green
}}

'''Paris green''' (copper(II) acetate triarsenite or copper(II) acetoarsenite) is an [[arsenic]]-based [[organic compound|organic]] [[pigment]]. As a green pigment it is also known as '''Mitis green''', '''Schweinfurt green''', '''Sattler green''', '''[[emerald]]''', '''Vienna green''', '''Emperor green''' or '''Mountain green'''. It is a highly [[toxic]] emerald-green crystalline powder<ref>{{cite web|url=http://nj.gov/health/eoh/rtkweb/documents/fs/0529.pdf|title=Hazardous Substance Fact Sheet|publisher=NJ Dept. of Health and Senior Services|access-date=2011-02-07}}</ref> that has been used as a [[rodenticide]] and [[insecticide]],<ref>{{Cite journal|jstor = 41829377|title = Dangers in the Manufacture of Paris Green and Scheele's Green|journal = Monthly Review of the U.S. Bureau of Labor Statistics|volume = 5|issue = 2|pages = 78–83|year = 1917}}</ref> and also as a [[pigment]]. 

It was manufactured in 1814 to be a pigment to make a vibrant green paint, and was used by many notable painters in the 19th century. The color of Paris green is said to range from a pale blue green when very finely ground, to a deeper green when coarsely ground. Due to the presence of arsenic, the pigment is extremely toxic. In paintings, the color can degrade quickly.

==Preparation and structure==
Paris green may be prepared by combining [[copper(II) acetate]] and [[arsenic trioxide]].<ref name=Ullmann>"H.Wayne Richardson, "Copper Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a07_567}}</ref>  The structure was confirmed by [[X-ray crystallography]].<ref>{{cite journal |doi=10.1524/zkri.1977.145.1-2.35|title=Die Kristallstruktur von Cu<sub>2</sub>As<sub>3</sub>O<sub>6</sub>CH<sub>3</sub>COO|year= 1977|last1=Pertlik|first1=F.|journal=Zeitschrift für Kristallographie|volume=145|issue= 1–2|pages=35–45|bibcode=1977ZK....145...35P}}</ref>[[File:Subunit of Cu2As3O3(OAc) (ASOCUA).png|thumb|A subunit of the Cu<sub>2</sub>As<sub>3</sub>O<sub>6</sub>(OAc) framework, highlighting the [As<sub>3</sub>O<sub>6</sub><nowiki>]</nowiki><sup>3-</sup> ligand. Color code: Cu = blue, As = large gray, C = gray, O = red.|none]]

== History ==
In 1814, Paris green was invented by paint manufacturers Wilhelm Sattler and Friedrich Russ, in Schweinfurt, Germany for the Wilhelm Dye and White Lead Company. They were attempting to produce a more stable pigment than [[Scheele's green]], seeking to make a green that was less susceptible to darkening around sulfides.{{efn-lr|Sulfur was commonly produced from burning coal fires.}} In 1822, the recipe for emerald green was published by Justus von Liebig and André Braconnot.<ref>{{Cite web |last=Zieske |first=Faith |date=1995 |title=An Investigation of Paul Cézanne's Watercolors With Emphasis on Emerald |url=https://cool.culturalheritage.org/coolaic/sg/bpg/annual/v14/bp14-09.html |website=The Book and Paper Group: Annual}}</ref> 

In 1867, the pigment was named Paris green and was officially recognized as the first chemical insecticide in the world. Because of its arsenic content, the pigment was dangerous and toxic to manufacture, often resulting in factory poisonings.<ref>{{Cite book |last=Haynes |first=William |title=American Chemical Industry: Background and Beginnings |publisher=D. Van Nostrand Company, Inc. |year=1954 |edition=Vol. 1 |pages=355–369}}</ref><ref>{{Cite book |last=Emsley |first=John |url=https://archive.org/details/elementsofmurder00emsl |title=The Elements of Murder: A History of Poison |publisher=[[Oxford University Press|OUP]] |year=2005 |isbn=9780192805997 |page=[https://archive.org/details/elementsofmurder00emsl/page/118 118] |url-access=registration}}</ref> At the time, emerald green was praised as a more durable and vibrant substitute for Scheele's green, even though it would later prove to degrade quickly and react with other manufactured paints.{{Citation needed|date=April 2023}}

== Pigment ==
In paintings, the pigment produces a rich, dark green with an undertone of blue. In comparison, Scheele's green is more yellow, and therefore, more lime-green.<ref name=":0">{{Cite book |last1=Fiedler |first1=Inge |title=Artists' Pigments: A Handbook of Their History and Characteristics |last2=Bayard |first2=Michael A. |publisher=National Gallery of Art |year=2012 |volume=3 |location=Washington D.C. |pages=219–71 |chapter=Emerald Green and Scheele's Green}}</ref>{{Rp|page=220}} Paris green became popular in the 19th century because of its brilliant color.<ref name=":0" />{{Rp|page=223}} It was also called [[emerald]] green because of its resemblance to the gemstone's deep color.

=== Permanence ===
[[File:Paris Green (Schweinfurter Grün).JPG|thumb|Can of Paris green pigment by Sherwin-Williams Co.|left]]
The pigment has a tendency to darken and turn brown. The issue was already apparent in the 19th century. In a 1888 study, watercolors with the pigment were shown to darken and turn brown when exposed to natural light and air. Experiments at the turn of the 20th century gave mixed results. Some found that the Paris green degraded slightly while other sources said the pigment was weatherproof.<ref name=":0" />{{Rp|page=227}} This discrepancy could be due to the fact that each experiment used a different brand of Paris green.<ref name=":0" />{{Rp|page=228}}

Paris green in ''Descente des Vaches'' by [[Théodore Rousseau]] has changed significantly.<ref>{{Cite journal |last1=Keune |first1=Katrien |last2=Boon |first2=Jaap J. |last3=Boitelle |first3=R. |last4=Shimazdu |first4=Y. |date=July 2013 |title=Degradation of Emerald Green in Oil Paint and Its Contribution to the Rapid Change in Colour of the Descente Des Vaches (1834-1835) |url=https://www.jstor.org/stable/42751821 |journal=Studies in Conservation |volume=58 |issue=3 |pages=199–210 |doi=10.1179/2047058412Y.0000000063 |jstor=42751821 |via=JSTOR}}</ref>

====Related pigments====
Similar natural compounds are the minerals [[chalcophyllite]] {{chem|Cu|18|Al|2|(AsO|4|)|3|(SO|4|)|3|(OH)|27}}·36{{chem|H|2|O}}, [[conichalcite]] {{chem|CaCu(AsO|4|)(OH)}}, [[cornubite]] {{chem|Cu|5|(AsO|4|)|2|(OH)|4}}·{{chem|H|2|O}}, [[cornwallite]] {{chem|Cu|5|(AsO|4|)|2|(OH)|4}}·{{chem|H|2|O}}, and [[liroconite]] {{chem|Cu|2|Al(AsO|4|)(OH)|4}}·4{{chem|H|2|O}}. These minerals range in color from greenish blue to slightly yellowish green.{{Citation needed|date=March 2021}}

[[Scheele's green]] is a chemically simpler, less brilliant, and less permanent, copper-arsenic pigment used for a rather short time before Paris green was first prepared, which was approximately 1814. It was popular as a [[wallpaper]] pigment and would degrade, with moisture and molds, to [[arsine]] gas. Paris green was used in wallpaper to some extent and may have degraded similarly.<ref>{{Cite web |last=Zawacki |first=Alexander J. |date=23 January 2018 |title=How a Library Handles a Rare and Deadly Book of Wallpaper Samples |url=http://www.atlasobscura.com/articles/shadows-from-the-walls-of-death-book |website=Atlas Obscura}}</ref> Both pigments were once used in [[printing]] [[ink]] formulations.{{Citation needed|date=March 2021}}

The [[ancient Rome|ancient Romans]] used one of them, possibly [[conichalcite]], as a green pigment. The Paris green paint used by the [[Impressionism|Impressionists]] is said to have been composed of relatively coarse particles. Later, the chemical was produced with increasingly small grinds and without carefully removing impurities. Its permanence suffered. It is likely that it was ground more finely for use in [[watercolor]]s and inks.{{Citation needed|date=March 2021}}

==Uses==

=== Painting ===
Paris green was widely used by 19th-century artists. It is present in several paintings by [[Claude Monet]] and [[Paul Gauguin]], who found its color difficult to replicate with natural materials.<ref name=":0" />{{Rp|page=256}}<ref>{{Cite web |last=Mars |first=Ashley Grove |date=2020-06-11 |title=Chrysler Museum of Art {{!}} |url=https://chrysler.org/the-history-of-art-in-colors-green/ |access-date=2024-08-03 |website=Chrysler Museum of Art |language=en}}</ref>
[[File:Van Gogh self-portrait dedicated to Gauguin.jpg|thumb|Vincent van Gogh, ''Self-Portrait (Dedicated to Paul Gauguin)'', September, 1888. Note the vivid background and undercoat of Paris green. ]]
[[File:Georges Seurat - Un dimanche après-midi à l'Île de la Grande Jatte v2.jpeg|none|thumb|432x432px|Georges Seurat, ''[[A Sunday Afternoon on the Island of La Grande Jatte|A Sunday on la Grande Jatte]]'': an example of a neo-Impressionist work using emerald green<ref>{{Cite web |last=Lipscher |first=Juraj |title="Georges Seurat, A Sunday on La Grande Jatte" |url=https://colourlex.com/project/georges-seurat-a-sunday-on-la-grande-jatte/#:~:text=His%20palette%20consisted%20of%20vermilion,matter%20was%20rendered%20more%20exacting. |website=Colorlex}}</ref>]]

=== Insecticide ===
In 1867, farmers in Illinois and Indiana found that Paris green was effective against the [[Colorado potato beetle]], an aggressive agricultural pest. Despite concerns regarding the safety of using arsenic compounds on food crops, Paris green became the preferred method for controlling the beetle. By the 1880s, Paris green had become the first widespread use of a chemical insecticide in the world.<ref name=Sor>Sorenson 1995</ref> It was also used widely in the Americas to control the tobacco budworm, ''[[Heliothis virescens]].''<ref>{{Cite journal|last=Blanco|first=Carlos|date=2012|title=Heliothis virescens and Bt cotton in the United States|journal=GM Crops & Food: Biotechnology in Agriculture and the Food Chain|volume=3|issue=3|pages=201–212|doi=10.4161/gmcr.21439|pmid=22892654|doi-access=free}}</ref> To kill [[codling moth]], it was mixed with [[calcium oxide|lime]] and sprayed on fruit trees.<ref>https://www.newspapers.com/image/505098962/?match=1&terms=Lime Minister of Agriculture of the United States Gives Advice, Victoria Daily Times, March 27, 1895, p.2.</ref>

Paris green was heavily sprayed by airplane in [[Italy]], Sardinia, and [[Corsica]] during 1944 and in Italy in 1945 to control [[malaria]].<ref>{{cite web
| url = http://history.amedd.army.mil/booksdocs/wwii/Malaria/chapterV.htm
| title = Preventive Medicine in World War II, Chapter V. North Africa, Italy, and the Islands of the Mediterranean
| access-date = 2008-09-30
| author = Justin M. Andrews, Sc. D.
| year = 1963
| publisher = Office of the Surgeon General, Department of the Army
| location = Washington, D.C. USA
| pages = 281
}}</ref> It was once used to kill rats in [[Parisian sewers]], which is how it acquired its common name.<ref>''The Natural Paint Book'', by Lynn Edwards, Julia Lawless,  Table of contents</ref>

However, the manufacturing of the insecticide caused many health complications for factory workers, and in certain cases was lethal.<ref>{{Cite book |last=Whorton |first=James C. |url=https://books.google.com/books?id=YnVNX3drptkC&pg=PT162 |title=The Arsenic Century: How Victorian Britain was Poisoned at Home, Work, and Play |publisher=[[Oxford University Press|OUP]] |year=2010 |isbn=9780191623431 |page=162}}</ref>
<!--sez who?: The exterior of the [[Ulysses S. Grant National Historic Site|home of Ulysses S. Grant]] was painted with this pigment.<ref>{{cite web|url=http://www.nps.gov/ulsg/faqs.htm|title=Ulysses S. Grant National Historic Site - Frequently Asked Questions|publisher=[[National Park Service]]|access-date=2010-12-02}}</ref> It was also the pigment used to paint [[window shutter]]s, signs, etc. It blackens when exposed due to the instability of the molecule, instability that appears to be increased when the chemical is produced with a very fine particle size and isn't washed to remove impurities. Much of the blackening may be due to its reactivity with [[sulfur]], as sulfur-containing compounds are common in painting (such as [[cadmium sulfide]]) and in air due to [[air pollution]]. In oils, artists often isolated Paris green with [[varnish]] to reduce its tendency to darken, a practice that is suggested for all arsenic pigments, such as [[orpiment]]. It has become the norm in parts of America to paint shutters a dark green color because people mistakenly believe the tradition was to paint them such a dark hue. In fact, shutters were commonly painted with Paris green.-->
<!--sez who?: Arsenic based green also is a very old [[dye]] for cloth, but its use was eventually abandoned because those who wore clothes so dyed tended to come to early ends, without the substance's toxicity being formally recognized. To this day, French theater costumes traditionally eschew the color green.-->
<!--Irrelevant:The permanent purple pigment [[cobalt violet]], also used by the Impressionists, was once formulated with arsenic. It was reformulated successfully without arsenic in two varieties, "light" with [[ammonium]] or [[lithium]] and "deep" without. It was useful to artists and others in need of a brilliant green pigment for a compound similar to Paris green to be synthesized without arsenic.-->

{{Gallery
| title=Illustrations of Paris green
| width=250 | height=250 | align=center
|| Paris green pigment
| File:3298054073 103cba6cc2 oMélangeVertParis (restored and cropped).jpg | Mixing "Paris green" and road dust preparatory to dusting streams and breeding places of mosquitoes during [[World War II]]
| File:"Dust Paris green on swamps and ponds" - NARA - 515024 (restored).jpg|Use as insecticide, poster issued by US Public Health Service
}}

=== Bookbindings ===
Throughout the 19th century, Paris green and similar arsenic pigments were used in books, particularly on bookcloth coverings, textblock edges, decorative labels and onlays, and in printed or manual [[book illustration|illustration]]s. The colorant is particularly prevalent in bookbindings from the 1850s and 1860s published in Germany, England, France, and the United States. Use of arsenic-containing pigments waned in the later part of the 19th-century with heightened awareness of their toxicity and the availability of less toxic chromium- and cobalt-based alternatives. Since February 2024, several German libraries have started to block public access to their stock of 19th century books, to check for the degree of poisoning.<ref>{{cite web |title=Information zum Umgang mit potentiell gesundheitsschädigenden Pigmentbestandteilen an historischen Bibliotheksbeständen (hier: arsenhaltige Pigmente) |language=de |trans-title= |date=December 2023 |author=dbv-Kommission Bestandserhaltung |website=www.bibliotheksverband.de |publisher= |url=https://www.bibliotheksverband.de/sites/default/files/2024-01/ArsenHandreichung2023-12-08.pdf |access-date=2024-03-17 |url-status=live |archive-url=https://web.archive.org/web/20240317204413/https://www.bibliotheksverband.de/sites/default/files/2024-01/ArsenHandreichung2023-12-08.pdf |archive-date=2024-03-17}} (6 pages)</ref><ref>{{cite web |title=Arsenbelastete Bücher |language=de |trans-title=Arsen contaminated books |website=www.uni-bielefeld.de |date=2024 |publisher=[[Universität Bielefeld]] |url=https://www.uni-bielefeld.de/ub/arsenic_contamination/ |access-date=2024-03-06 |url-status=live |archive-url=https://web.archive.org/web/20240311093305/https://www.uni-bielefeld.de/ub/arsenic_contamination/ |archive-date=2024-03-11}}</ref><ref>{{cite web |title=Werke aus dem 19. Jahrhundert: Arsenverdacht – Unibibliothek überprüft 15.000 Bücher |language=de |trans-title= |author= |website=www.spiegel.de |date=2024-03-06 |url=https://www.spiegel.de/panorama/bildung/arsen-verdacht-unibibliothek-duesseldorf-nimmt-15-000-buecher-aus-den-regalen-a-9ef87fd9-0ff9-41c9-abc0-ca9e2f40e505 |access-date=2024-03-06 |url-status=live |archive-url=https://web.archive.org/web/20240317203814/https://www.spiegel.de/panorama/bildung/arsen-verdacht-unibibliothek-duesseldorf-nimmt-15-000-buecher-aus-den-regalen-a-9ef87fd9-0ff9-41c9-abc0-ca9e2f40e505 |archive-date=2024-03-17}}</ref><ref>{{cite web |title=Aktuelles: Information zum Umgang mit potentiell gesundheitsschädigenden Pigmentbestandteilen, wie arsenhaltigen Pigmenten, an historischen Bibliotheksbeständen |language=de |trans-title= |website=www.bibliotheksverband.de |date=2024-02-29 |author=dbv-Kommission Bestandserhaltung |url=https://www.bibliotheksverband.de/aktuelles |access-date=2024-03-06 |url-status= |archive-url= |archive-date=}}</ref><ref name="Pilz_2024">{{cite web |title=Warum von grünen Büchern eine Gefahr ausgeht |language=de |trans-title=Why green books are dangerous |date=2024-03-04 |author-first=Michael |author-last=Pilz |work=Welt |department=Kultur > Arsen |url=https://www.welt.de/kultur/article250348708/Buecher-Warum-von-gruenen-Buechern-eine-Gefahr-ausgeht.html |access-date=2024-03-17 |url-status=live |archive-url=https://web.archive.org/web/20240304173848/https://www.welt.de/kultur/article250348708/Buecher-Warum-von-gruenen-Buechern-eine-Gefahr-ausgeht.html |archive-date=2024-03-04}}</ref><ref>{{cite web |author=University of Delaware |title=Arsenic Bookbindings {{!}} Poison Book Project |url=https://sites.udel.edu/poisonbookproject/arsenic-bookbindings/ |website=Poison Book Project}}</ref> The [[Poison Book Project]] has cataloged books with these bindings.

===Wallpaper===
Paris green became a popular paint in mass-produced wallpaper, which is believed to have shortened lifespans.<ref>{{cite journal |last1=Bartrip |first1=P. W. J. |title=How Green Was My Valance?: Environmental Arsenic Poisoning and the Victorian Domestic Ideal |journal=The English Historical Review |date=1994 |volume=109 |issue=433 |pages=891–913 |url=https://www.jstor.org/stable/574537 |issn=0013-8266}}</ref> Wallpaper swatches from this era have been preserved in the book ''[[Shadows from the Walls of Death]]''.

==See also==
* [[List of colors]]
* [[List of inorganic pigments]]

==References==
{{Notelist-lr}}

{{reflist}}

==Further reading==
* Fiedler, I. and Bayard, M. A., "Emerald Green and Scheele’s Green", in ''Artists' Pigments: A Handbook of Their History and Characteristics'', Vol. 3: E.W. Fitzhugh (Ed.) Oxford University Press 1997, pp.&nbsp;219–271
* {{cite journal |last1=Hughes |first1=Michael F. |display-authors=etal |title=Arsenic Exposure and Toxicology: A Historical Perspective |journal=Toxicological Sciences |date=2011 |volume=123 |issue=2 |pages=305–332 |pmc=3179678 |pmid=21750349 |doi=10.1093/toxsci/kfr184 }}
* {{cite book|last1=Sorensen|first1=W. Conner|title=Brethren of the Net, American Entomology, 1840-1880|date=1995|publisher=University of Alabama Press|pages=124–125}}
* Spear, Robert J., The Great Gypsy Moth War, A History of the First Campaign in Massachusetts to Eradicate the Gypsy Moth, 1890–1901. University of Massachusetts Press, Amherst and Boston, 2005. {{ISBN|1-55849-479-0}}

==External links==
* [https://www.atsdr.cdc.gov/csem/csem.html Case Studies in Environmental Medicine - Arsenic Toxicity]
* [http://webexhibits.org/pigments/indiv/recipe/emerald.html How Emerald green is made]
* [https://web.archive.org/web/20080302034606/http://www.npi.gov.au/database/substance-info/profiles/27.html National Pollutant Inventory - Copper and compounds fact sheet]
* [http://colourlex.com/project/emerald-green/ Emerald green, Colourlex]

{{Acetates}}
{{Shades of green}}

[[Category:Acetates]]
[[Category:Arsenites]]
[[Category:Copper(II) compounds]]
[[Category:Insecticides]]
[[Category:Organic pigments]]
[[Category:Rodenticides]]
[[Category:Shades of green]]