White lead: Difference between revisions

| Watchedfields = changed

| verifiedrevid = 438439590

| ImageFile = Lead carbonate hydroxide.gif

| ImageSize =

| IUPACName =

| OtherNames = Basic lead carbonate

| Section1 = {{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|CAS}}

| ChemSpiderID = 14148

| EINECS = 215-290-6

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = WDF96425HV

| PubChem = 14834

| StdInChI=1S/2CH2O3.2H2O.3Pb/c2*2-1(3)4;;;;;/h2*(H2,2,3,4);2*1H2;;;/q;;;;3*+2/p-6

| StdInChIKey = RYZCLUQMCYZBJQ-UHFFFAOYSA-H

| SMILES = C(=O)([O-])[O-].C(=O)([O-])[O-].[OH-].[OH-].[Pb+2].[Pb+2].[Pb+2]

}}

| Section2 = {{Chembox Properties

| Formula = 2PbCO₃·Pb(OH)₂

| MolarMass = 775.633 g/mol

| Appearance = White powder

| Density =

| MeltingPt =

| BoilingPt =

| Solubility =

| Section3 = {{Chembox Hazards

| MainHazards = Lead poisoning

| GHSPictograms = {{GHS07}}{{GHS08}}{{GHS09}}

| GHSSignalWord =

| HPhrases = {{H-phrases|302|332|360|373|410}}

| PPhrases = {{P-phrases|201|202|260|261|264|270|271|273|281|301+312|304+312|304+340|308+313|312|314|330|391|405|501}}

| FlashPt =

| AutoignitionPt =

[[File:Vasa color pigments.jpg|thumb|Color pigments used on the warship [[Vasa (ship)|Vasa]], with white lead second from left, bottom shelf]]

'''White lead''' is the basic lead carbonate 2PbCO₃·Pb(OH)₂.<ref name="Wiberg">{{cite book|title=Inorganic Chemistry |author1-first=Egon |author1-last=Wiberg |author2-first=Arnold Frederick |author2-last=Holleman |publisher=Elsevier |year=2001 |isbn=0-12-352651-5}}</ref> It is a complex [[Salt (chemistry)|salt]], containing both carbonate and hydroxide ions. White lead occurs naturally as a mineral, in which context it is known as '''hydrocerussite''',<ref name="Wiberg"/> a [[hydrate]] of [[cerussite]].<ref>''see'' [[mineral hydration]]</ref> It was formerly used as an ingredient for [[lead paint]] and a cosmetic called [[Venetian ceruse]], because of its [[Opacity (optics)|opacity]] and the satiny smooth mixture it made with dryable oils. However, it tended to cause [[lead poisoning]], and its use has been banned in most countries.<ref>{{cite journal |url=http://rachel.org/files/document/Lead_Poisoning_in_Historical_Perspective.pdf |last=Hernberg |first=Sven |title=Lead Poisoning in a Historical Perspective |journal=American Journal of Industrial Medicine |volume=38 |issue=3 |pages=244–254 |date=September 2000 |doi=10.1002/1097-0274(200009)38:3<244::AID-AJIM3>3.0.CO;2-F |pmid=10940962 |citeseerx=10.1.1.477.2081 |access-date=2015-04-12 |archive-date=2013-04-13 |archive-url=https://web.archive.org/web/20130413014235/http://rachel.org/files/document/Lead_Poisoning_in_Historical_Perspective.pdf |url-status=dead }}</ref>

White lead compounds known as [[Metallic soap|lead soap]] were also used as additive for lubricants for [[bearing (mechanical)|bearings]] and in machine shops.<ref>{{cite book|last=Klemgard|first=E.N.|chapter=Lead base greases|title=Lubricating Greases Their Manufacture And Use|year=1937|publisher=Reinhold Publishing Corporation|pages=677|url=https://archive.org/details/in.ernet.dli.2015.84129}}</ref> Lead soap was also used as an [[oil drying agent]] for paints made with [[drying oil]] or air drying paints made with [[alkyd resin]]s. Lead is often used with cobalt driers. Lead free substitutes have been developed to replace this use of lead in paint.

==History==

What is commonly known today as the "Dutch method" for the preparation of white lead was described as early as [[Theophrastus|Theophrastus of Eresos]]<ref>[[J. R. Partington]], ''[[q:J. R. Partington#A Short History of Chemistry .281937.29|A Short History of Chemistry]]'' (1937)</ref> (ca. 300 BC), in his brief work on rocks or minerals, [[Theophrastus#On Stones|''On Stones'']] or ''History of Stones.'' His directions for the process were repeated throughout history by many authors of chemical and [[Alchemy|alchemical]] literature. The uses of cerussa were described as an external medication and pigment.<ref>{{cite book|last=Stillman|first=John Maxson|title=The Story of Early Chemistry|url=https://archive.org/details/in.ernet.dli.2015.179875|year=1924|publisher=D. Appleton|pages=[https://archive.org/details/in.ernet.dli.2015.179875/page/n37 19]–20}}</ref>

Clifford Dyer Holley quotes from Theophrastus' ''History of Stones''<ref>Theophrastus, ''History of Stones'', p.223</ref> as follows, in his book ''The Lead and Zinc Pigments''.

{{blockquote|text=

Lead is placed in earthen vessels over sharp vinegar, and after it has acquired some thickness of a sort of rust, which it commonly does in about ten days, they open the vessels and scrape it off, as it were, in a sort of foulness; they then place the lead over vinegar again, repeating over and over again the same method of scraping it till it has wholly dissolved. What has been scraped off they then beat to powder and boil for a long time, and what at last subsides to the bottom of the vessel is ceruse.<ref>{{cite book|last=Holley|first=Clifford Dyer|title=The Lead and Zinc Pigments|url=https://archive.org/details/dli.bengal.10689.2347|year=1909|publisher=John Wiley & Sons|page=[https://archive.org/details/dli.bengal.10689.2347/page/n22 2]}}</ref>

}}

Later descriptions of the Dutch process involved casting metallic [[lead]] as thin buckles and corroded with [[acetic acid]] in the presence of [[carbon dioxide]]. This was done by placing them over pots with a little [[vinegar]] (which contains acetic acid). These were stacked up and covered with a mixture of decaying dung and spent [[tanbark|tanner's bark]], which supplied the CO₂, and left for six to fourteen weeks, by which time the blue-grey lead had corroded to white lead. The pots were then taken to a separating table where scraping and pounding removed the white lead from the buckles. The powder was then dried and packed for shipment or shipped as a paste.<ref>[http://www.lead411.org/Templates/history/white_lead_pigment.htm Lead411.org] {{Webarchive|url=https://web.archive.org/web/20080403001351/http://www.lead411.org/Templates/history/white_lead_pigment.htm |date=2008-04-03 }} based on Warren, Christian. "Toxic Purity: The progressive era origins of America’s lead paint poisoning epidemic". ''Business History Review''. Winter 1999, Vol. 73(4)</ref> One benefit of the process was that it was not necessary to dry the paste of white lead, removing its water. All that needed was to mill the paste with [[linseed oil]], and the white lead would take up the oil and reject the residual water, to give white lead in oil. {{Citation needed|date=June 2013}}

==Paints==

{{Main|Lead white}}

[[File:Lead Paint2.JPG|thumb|left|Can of ''Dutch Boy Paint'', consisting of basic lead carbonate and [[linseed oil]]]]

White lead has been the principal white pigment of classical European [[oil painting]]. There have been claims that it is partly responsible for darkening of old paintings over time, reacting with trace amounts of [[hydrogen sulfide]] in the air to produce black [[lead sulfide]]. Other authorities dispute this; the most traditional view is that impermanent pigments and dirty varnish (which is often cleanable) are more likely responsible for darkening.{{Citation needed|date=June 2013}}

White lead has been mostly supplanted in artistic use by [[Titanium dioxide|titanium white]], which has much higher tinting strength than white lead.<ref>{{cite book|last=Laver |first=M. |chapter=Titanium Dioxide Whites |editor-last=Fitzhugh |editor-first= E. W. |title=Artists' Pigments |volume=3 |publisher=Oxford University Press |year=1997 |page=309}}</ref> Critics argue that substitutes like zinc oxide and titanium dioxide are more reactive, become brittle, and can flake off.<ref name="naturalpigments2">{{cite web|title=Zinc White: Problems in Oil Paint |url=https://www.naturalpigments.com/artist-materials/zinc-white-oil-paint-color/}} The Smithsonian's Museum Conservation Institute exposes long-term problems with zinc white</ref><ref>{{cite journal |last1=Macchia |first1=Andrea |last2=Cesaro |first2=Stella |last3=Keheyan |first3=Yeghis |last4=Ruffolo |first4=Silvestro |last5=La Russa |first5=Mauro |title=White zinc in Linseed Oil Paintings: Chemical, Mechanical and Aesthetic Aspects |journal=Periodico di Mineralogia |date=2015 |volume=84 |issue=3A |pages=483–495 |doi=10.2451/2015PM0027}}</ref> White lead is less used by today's painters, not because of its toxicity directly; but simply because its toxicity in other contexts has led to trade restrictions that make white lead difficult for artists to obtain in sufficient quantities.<ref>{{cite journal |last1=Raine |first1=Craig |title=Epic of gossip (review of ''The Lives of Lucian Freud : Fame 1968-2011'' by William Feaver |journal=The Spectator |date=5 September 2020 |page=30/2}}</ref> [[Winsor & Newton]], the English paint company, was restricted in 2014 from selling its flake white in tubes and now must sell exclusively in {{cvt|150|ml}} tins.<ref>{{cite web |title=Choosing a white in oil colour |url=http://www.winsornewton.com/na/discover/tips-and-techniques/oil-colour/choosing-a-white-in-oil-colour-us |website=Winsor & Newton |access-date=18 October 2014 |quote="For reasons of toxicity these Lead White colours are only available in tins in the EU." |archive-date=8 October 2014 |archive-url=https://web.archive.org/web/20141008003654/http://www.winsornewton.com/na/discover/tips-and-techniques/oil-colour/choosing-a-white-in-oil-colour-us |url-status=dead }}</ref>

In the eighteenth century, white lead paints were routinely used to repaint the hulls and floors of [[Royal Navy]] vessels, to waterproof the timbers and limit infestation by [[teredo navalis|shipworm]].<ref>{{cite book|title=Captain James Cook |first=Richard |last=Hough |year=1994 |publisher=Hodder and Stoughton |page=56 |isbn=978-0-340-82556-3}}</ref>

===Other synonyms (as an art pigment)===

Among the synonyms for white lead are Berlin white, [[Cremnitz]] white, Dutch white lead, flake white, Flemish white, Krems white, London white, Pigment White 1, Roman white, silver white, slate white and Vienna white.<ref>{{cite web |title=Lead white |url=http://cameo.mfa.org/wiki/Lead_white |website=Conservation and Art Materials Encyclopedia Online (CAMEO) |publisher=Museum of Fine Arts, Boston (Massachusetts) |access-date=6 June 2019}}</ref>

* [[List of inorganic pigments]]

* [[Venetian ceruse]]

==Further reading==

* Gettens, R.J., Kühn, H. and Chase, W.T. "Lead White", in Roy, A., (Ed), ''Artists' Pigments'', Vol 2, Oxford University Press, 1993, pp.&nbsp;67–81

==External links==

{{NSRW Poster|White Lead}}

* [http://colourlex.com/project/lead-white/ Lead white], Colourlex

{{lead compounds}}

{{Authority control}}

[[Category:Lead(II) compounds]]

[[Category:Inorganic pigments]]

[[Category:Environmental impact of paint]]