{{short description|Chemical compound}} {{About-distinguish|the trichloride|chloroauric acid}} {{good article}} {{Use British English|date=June 2021}} {{Chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 443849746 | ImageFile1 = AuCl3 structure.svg | ImageClass1 = skin-invert-image | ImageSize1 = | ImageCaption1 = | ImageFile2 = Gold(III)-chloride-dimer-3D-balls.png | ImageClass2 = bg-transparent | ImageSize2 = | ImageCaption2 = Ball-and-stick model of AuCl<sub>3</sub> | ImageFile3 = Gold(III)-chloride-xtal-3D-SF-B.png | ImageClass3 = bg-transparent | ImageSize3 = | ImageCaption3 = Crystal structure of AuCl<sub>3</sub> | IUPACName = Gold(III) trichloride | OtherNames = Auric chloride<br />Gold trichloride |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 24244 | PubChem = 26030 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 15443PR153 | InChI = 1/Au.3ClH/h;3*1H/q+3;;;/p-3 | InChIKey = RJHLTVSLYWWTEF-DFZHHIFOAC | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/Au.3ClH/h;3*1H/q+3;;;/p-3 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = RJHLTVSLYWWTEF-UHFFFAOYSA-K | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 30076 | SMILES = Cl[Au-]1(Cl)[Cl+][Au-]([Cl+]1)(Cl)Cl <!-- [Cl-][Au+3]1([Cl-])[Cl-][Au+3]([Cl-]1)([Cl-])[Cl-] and Cl[Au+3]1(Cl)[Cl-3][Au+3]([Cl-3]1)(Cl)Cl have the right structure, but in those SMILES, the gold isn't in the +III oxidation state. --> | CASNo = 13453-07-1 | CASNo_Ref = {{cascite|correct|CAS}} | RTECS = MD5420000 }} |Section2={{Chembox Properties | Formula = {{chem2|AuCl3}}<br />(exists as {{chem2|Au2Cl6}}) | MolarMass = 606.6511&nbsp;g/mol (for {{chem2|Au2Cl6}}) | Appearance = Red crystals (anhydrous); golden, yellow crystals (monohydrate)<ref name="wiberg_holleman"/> | Density = 4.7&nbsp;g/cm<sup>3</sup> | Solubility = 68&nbsp;g/100 ml (20 °C) | SolubleOther = soluble in ether and ethanol, slightly soluble in liquid ammonia, insoluble in benzene | MeltingPtC = 160 | MeltingPt_notes = (decomposes) | MagSus = −112·10<sup>−6</sup> cm<sup>3</sup>/mol }} |Section3={{Chembox Structure | Coordination = Square planar | CrystalStruct = monoclinic | SpaceGroup = P2<sub>1</sub>/C | PointGroup = | LattConst_a = 6.57 Å | LattConst_b = 11.04 Å | LattConst_c = 6.44 Å | LattConst_alpha = | LattConst_beta = 113.3 | LattConst_gamma = | LattConst_ref =<ref name="crys" /> }} | Section4 = {{Chembox Thermochemistry | Thermochemistry_ref = | HeatCapacity = | Entropy = | DeltaHform = −117.6&nbsp;kJ/mol<ref>{{Cite book |title=CRC Handbook of Chemistry and Physics: A Ready-reference Book of Chemical and Physical Data |date=2016 |editor-first1=William M.|editor-last1= Haynes|editor-first2= David R.|editor-last2= Lide|editor-first3= Thomas J.|editor-last3= Bruno |isbn=978-1-4987-5428-6 |edition=95th |location=Boca Raton, Florida |oclc=930681942 |page=5-5}}</ref> | DeltaGfree = | DeltaHcombust = | DeltaHfus = | DeltaHvap = | DeltaHsublim = | HHV = | LHV = }} |Section7={{Chembox Hazards | Hazards_ref =<ref name=sds>{{cite web|title =Gold Chloride|url=https://www.americanelements.com/gold-chloride-13453-07-1|publisher = American Elements|access-date = July 22, 2019}}</ref> | ExternalSDS = | GHSPictograms = {{GHS07}} | GHSSignalWord = Warning | HPhrases = {{H-phrases|315|319|335}} | PPhrases = {{P-phrases|261|264|271|280|302+352|305+351+338}} | MainHazards = Irritant }} |Section8={{Chembox Related | OtherAnions = Gold(III) fluoride<br />Gold(III) bromide | OtherCations = Gold(I) chloride<br />Silver(I) chloride<br />Platinum(II) chloride<br />Mercury(II) chloride}} }} '''Gold(III) chloride''', traditionally called '''auric chloride''', is an inorganic compound of gold and chlorine with the molecular formula {{chem2|Au2Cl6}}. The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. It has two forms, the monohydrate (AuCl<sub>3</sub>·H<sub>2</sub>O) and the anhydrous form, which are both hygroscopic and light-sensitive solids. This compound is a dimer of {{chem2|AuCl3}}. This compound has a few uses, such as an oxidizing agent and for catalyzing various organic reactions.

==Structure== {{chem2|AuCl3}} exists as a chloride-bridged dimer both as a solid and vapour, at least at low temperatures.<ref name="crys">{{cite journal | author = E. S. Clark | author2 = D. H. Templeton | author3 = C. H. MacGillavry | year = 1958 | title = The crystal structure of gold(III) chloride | journal = Acta Crystallogr. | volume = 11 | issue = 4| pages = 284–288 | doi = 10.1107/S0365110X58000694 | url = http://scripts.iucr.org/cgi-bin/paper?S0365110X58000694 | access-date = 2010-05-21| doi-access = free }}</ref> Gold(III) bromide behaves analogously.<ref name="wiberg_holleman"/> The structure is similar to that of iodine(III) chloride.

Each gold center is square planar in gold(III) chloride, which is typical of a metal complex with a d<sup>8</sup> electron count. The bonding in {{chem2|AuCl3}} is considered somewhat covalent.<ref name="wiberg_holleman"/><!--, reflecting the high oxidation state and relatively high (for a metal) electronegativity of gold. So Au(II) is less covalent?--> <!--Reply to comment: yes. Think about how you can't get oxo compounds of most low oxidation state transition metals but can with higher OS.-->

==Properties== Gold(III) chloride is a diamagnetic light-sensitive red crystalline solid that forms the orange monohydrate, AuCl<sub>3</sub> · H<sub>2</sub>O; the anhydrous and monohydrate are both hygroscopic. The anhydrous form absorbs moisture from the air to form the monohydrate which can be reversed by the addition of thionyl chloride.<ref name="encyclo" />

==Preparation== Gold(III) chloride was first prepared in 1666 by Robert Boyle by the reaction of metallic gold and chlorine gas at 180&nbsp;°C:<ref name="wiberg_holleman">{{Cite book | author1 = Egon Wiberg | author2 = Nils Wiberg | author3 = A. F. Holleman | year = 2001 | title = Inorganic Chemistry| edition = 101 | publisher = Academic Press| isbn = 978-0-12-352651-9| pages = 1286–1287 }}</ref><ref>{{cite book |author1=Robert Boyle |author1-link=Robert Boyle |title=The origine of formes and qualities |date=1666 |page=370 |url=http://name.umdl.umich.edu/A29017.0001.001 |language=en}}</ref><ref>{{cite journal |author1=Thomas Kirke Rose |title=The dissociation of chloride of gold |journal=Journal of the Chemical Society, Transactions |date=1895 |volume=67 |pages=881–904 |doi=10.1039/CT8956700881 |url=https://zenodo.org/record/1784163 |language=en}}</ref> :{{chem2|2 Au + 3 Cl2 → Au2Cl6}} This method is the most common method of preparing gold(III) chloride. It can also be prepared by reacting gold powder with iodine monochloride:<ref name="encyclo" /> :2 Au + 6 ICl → 2 AuCl<sub>3</sub> + 3 I<sub>2</sub>

The chlorination reaction can be conducted in the presence of tetrabutylammonium chloride, the product being the lipophilic salt tetrabutylammonium tetrachloraurate.<ref>{{cite journal |doi=10.1071/C97029|title=Reduction of &#91;NBu4&#93;&#91;AuCl4&#93; to &#91;NBu4&#93;&#91;AuCl2&#93; with Sodium Acetylacetonate|year=1997|last1=Buckley|first1=Robbie W.|last2=Healy|first2=Peter C.|last3=Loughlin|first3=Wendy A.|journal=Australian Journal of Chemistry|volume=50|issue=7|page=775}}</ref>

Another method of preparation is via chloroauric acid, which is obtained by first dissolving the gold powder in aqua regia to give chloroauric acid:<ref>{{cite book |doi=10.1002/9780470132357.ch4|chapter=Gold Powder and Potassium Tetrabromoaurate(III)|series=Inorganic Syntheses|year=1953|volume=4|last1=Block|first1=B. P.|title=Inorganic Syntheses |pages=14–17|isbn=9780470132357}}</ref> :{{chem2|Au + HNO3 + 4 HCl → H[AuCl4] + 2 H2O + NO}} The resulting chloroauric acid is subsequently heated in an inert atmosphere at around 100&nbsp;°C to give {{chem2|Au2Cl6}}:<ref name="decomp">{{cite journal |author1=Ya-jie Zheng |author2=Wei Guo |author3=Meng Bai |author4=Xing-wen Yang |title=Preparation of chloroauric acid and its thermal decomposition |journal=The Chinese Journal of Nonferrous Metals |date=2006 |volume=16 |issue=11 |pages=1976–1982 |url=http://ysxb.csu.edu.cn/previewFile?id=36231978&type=pdf&lang=en |archive-url= https://web.archive.org/web/20240327045836/http://ysxb.csu.edu.cn/previewFile?id=36231978&type=pdf&lang=en|archive-date= March 27, 2024|language=chinese}}</ref><ref name="aero" /> :{{chem2|2 H[AuCl4] → Au2Cl6 + 2 HCl}}

==Reactions== 220px|right|thumb|Concentrated aqueous solution of gold(III) chloride

===Decomposition=== Anhydrous {{chem2|AuCl3}} begins to decompose to AuCl (gold(I) chloride) at around {{convert|160|°C}}; however, this, in turn, undergoes disproportionation at higher temperatures to give gold metal and AuCl<sub>3</sub>:<ref name="encyclo">{{cite book |author1=Michael J. Coghlan |author2=Rene-Viet Nguyen |author3=Chao-Jun Li |author4=Daniel Pflästerer |author5=A. Stephen K. Hashmi |chapter=Gold(III) Chloride |title=Encyclopedia of Reagents for Organic Synthesis |date=2015 |pages=1–24 |doi=10.1002/047084289X.rn00325.pub3|isbn=9780470842898 }}</ref><ref name="decomp" /> :{{chem2|AuCl3 → AuCl + Cl2}} (160&nbsp;°C) :{{chem2|3 AuCl → AuCl3 + 2 Au}} (>210&nbsp;°C) Due to the disproportionation of AuCl, above 210&nbsp;°C, most of the gold is in the form of elemental gold.<ref name="vapor">{{cite journal |author1=Yiqin Chen |author2=Xuezeng Tian |author3=Wei Zeng |author4=Xupeng Zhu |author5=Hailong Hu |author6=Huigao Duan |title=Vapor-phase preparation of gold nanocrystals by chloroauric acid pyrolysis |journal=Journal of Colloid and Interface Science |date=2015 |volume=439 |pages=21–27 |doi=10.1016/j.jcis.2014.10.017 |publisher=Elsevier |pmid=25463171 |bibcode=2015JCIS..439...21C |language=en}}</ref><ref name="aero">{{cite journal |author1=Robert G. Palgrave |author2=Ivan P. Parkin |title=Aerosol Assisted Chemical Vapor Deposition of Gold and Nanocomposite Thin Films from Hydrogen Tetrachloroaurate(III) |journal=Chemistry of Materials |date=2007 |volume=19 |issue=19 |pages=4639–4647 |doi=10.1021/cm0629006 |publisher=ACS Publications |language=en}}</ref>

Gold(III) chloride is more stable in a chlorine atmosphere and can sublime at around 200&nbsp;°C without any decomposition. In a chlorine atmosphere, AuCl<sub>3</sub> decomposes at 254&nbsp;°C yielding AuCl which in turn decomposes at 282&nbsp;°C to elemental gold.<ref name="crys" /><ref name="aucl">{{cite journal |author1=E.M.W. Janssen |author2=J.C.W. Folmer |author3=G.A. Wiegers |title=The preparation and crystal structure of gold monochloride, AuCl |journal=Journal of the Less Common Metals |date=1974 |volume=38 |issue=1 |pages=71–76 |doi=10.1016/0022-5088(74)90204-5 |language=en}}</ref> This fact that no gold chlorides can exist above 400&nbsp;°C is used in the Miller process.<ref name="Ullmann">{{Cite book|title=Ullmann's Encyclopedia of Industrial Chemistry|author1=Hermann Renner |author2=Günther Schlamp|year=2000|isbn=978-3-527-30673-2|chapter=Gold, Gold Alloys, and Gold Compounds|pages=106–107 |doi=10.1002/14356007.a12_499}}</ref>

===Other reactions=== {{chem2|AuCl3}} is a Lewis acid and readily forms complexes. For example, it reacts with hydrochloric acid to form chloroauric acid ({{chem2|H[AuCl4]}}):<ref name="greenwood" /> :{{chem2|HCl + AuCl3 → H+ + [AuCl4]−}} Chloroauric acid is the product formed when gold dissolves in aqua regia.<ref name="greenwood" />

On contact with water, {{chem2|AuCl3}} forms acidic hydrates and the conjugate base {{chem2|[AuCl3(OH)]−}}. A {{chem2|Fe(2+)}} ion may reduce it, causing elemental gold to be precipitated from the solution.<ref name="wiberg_holleman"/><ref name="Cotton">Cotton, F.A.; Wilkinson, G.; Murillo, C.A.; Bochmann, M. ''Advanced Inorganic Chemistry''; John Wiley & Sons: New York, 1999; pp. 1101-1102</ref>

Other chloride sources, such as KCl, also convert {{chem2|AuCl3}} into {{chem2|[AuCl4]−}}. Aqueous solutions of {{chem2|AuCl3}} react with an aqueous base such as sodium hydroxide to form a precipitate of {{chem2|Au(OH)3}}, which will dissolve in excess NaOH to form sodium aurate ({{chem2|NaAuO2}}). If gently heated, {{chem2|Au(OH)3}} decomposes to gold(III) oxide, {{chem2|Au2O3}}, and then to gold metal.<ref name="greenwood">{{cite book |author1=N. N. Greenwood |author2=A. Earnshaw |title=Chemistry of the Elements |date=1997 |publisher=Butterworth-Heinemann |location=Oxford, UK |isbn=9780750633659 |pages=1184–1185 |edition=2 |language=en}}</ref><ref name="MerckIndex">''The Merck Index. An Encyclopaedia of Chemicals, Drugs and Biologicals''. 14. Ed., 2006, p. 780, {{ISBN|978-0-911910-00-1}}.</ref><ref>H. Nechamkin, ''The Chemistry of the Elements'', McGraw-Hill, New York, 1968, p. 222</ref><ref>A. F. Wells, ''Structural Inorganic Chemistry'', 5th ed., Oxford University Press, Oxford, UK, 1984, p. 909</ref>

Gold(III) chloride is the starting point for the chemical synthesis of many other gold compounds. For example, the reaction with potassium cyanide produces the water-soluble complex, {{chem2|K[Au(CN)4]}}:<ref>{{cite journal |author1=Henry K. Lutz |title=Synthesis and Analyses of KAu(CN)4 |journal=Honors Theses. |date=1961 |url=https://digitalworks.union.edu/theses/1986 |publisher=Union Digital Works |language=en}}</ref> :{{chem2|AuCl3 + 4 KCN → K[Au(CN)4] + 3 KCl}}

Gold(III) fluoride can be also produced from gold(III) chloride by reacting it with bromine trifluoride.<ref name="greenwood" />

Gold(III) chloride reacts with benzene under mild conditions (reaction times of a few minutes at room temperature) to produce the dimeric phenylgold(III) dichloride; a variety of other arenes undergo a similar reaction:<ref>{{Cite journal|last1=Li|first1=Zigang|last2=Brouwer|first2=Chad|last3=He|first3=Chuan|date=2008-08-01|title=Gold-Catalyzed Organic Transformations|journal=Chemical Reviews|volume=108|issue=8|pages=3239–3265|doi=10.1021/cr068434l|pmid=18613729|issn=0009-2665}}</ref> :{{chem2|2 PhH + Au2Cl6 → [PhAuCl2]2 + 2 HCl}}

Gold(III) chloride reacts with carbon monoxide in a variety of ways. For example, the reaction of anhydrous AuCl<sub>3</sub> and carbon monoxide under SOCl<sub>2</sub> produces gold(I,III) chloride with Au(CO)Cl as an intermediate:<ref>{{cite journal |author1=Daniela Belli Dell'Amico |author2=Fausto Calderazzo |author3=Fabio Marchetti |author4=Stefano Merlino |author5=Giovanni Perego |title=X-Ray crystal and molecular structure of Au4Cl8, the product of the reduction of Au2Cl6 by Au(CO)Cl |journal=Journal of the Chemical Society, Chemical Communications |date=1977 |pages=31–32 |doi=10.1039/C39770000031 |language=en}}</ref><ref>{{cite journal |author1=Daniela Belli Dell'Amico |author2=Fausto Calderazzo |author3=Fabio Marchetti |author4=Stefano Merlino |title=Synthesis and molecular structure of [Au4Cl8], and the isolation of [Pt(CO)Cl5]– in thionyl chloride |journal=Journal of the Chemical Society, Dalton Transactions |date=1982 |issue=11 |pages=2257–2260 |doi=10.1039/DT9820002257 |language=en}}</ref> :2 AuCl<sub>3</sub> + 2 CO → Au<sub>4</sub>Cl<sub>8</sub> + 2 COCl<sub>2</sub> If carbon monoxide is in excess, Au(CO)Cl is produced instead.<ref>{{cite book |chapter=Carbonylchlorogold(I) |date=1986 |volume=24 |pages=236–238 |doi=10.1002/9780470132555.ch66 |title=Inorganic Syntheses |last1=Dell'Amico |first1=D. Belli |last2=Calderazzo |first2=F. |last3=Murray |first3=H. H. |author4-link=John P. Fackler Jr. |last4=Fackler |first4=J. P. |isbn=9780470132555 }}</ref><ref name="cocl2" />

However, under tetrachloroethylene and at 120&nbsp;°C, gold(III) chloride is first reduced to gold(I) chloride, which further reacts to form Au(CO)Cl. AuCl<sub>3</sub> is also known to catalyze the production of phosgene.<ref name="cocl2">{{cite book |author1=T.A. Ryan |author2=E.A. Seddon |author3=K.R. Seddon |author4=C. Ryan |title=Phosgene And Related Carbonyl Halides |date=1996 |publisher=Elsevier Science |isbn=9780080538808 |pages=242–243 |language=en}}</ref><ref>{{cite journal |author1=M. S. Kharasch |author2=H. S. Isbell |title=The Chemistry of Organic Gold Compounds. I. Aurous Chloride Carbonyl and a Method of Linking Carbon to Carbon |journal=Journal of the American Chemical Society |date=1930 |volume=52 |issue=7 |pages=2919–2927 |doi=10.1021/ja01370a052 |language=en}}</ref>

==Applications== Gold(III) chloride has many uses in the laboratory, and primarily thrives in this environment.<ref name="encyclo" />

===Organic synthesis=== Since 2003, {{chem2|AuCl3}} has attracted the interest of organic chemists as a mild acid catalyst for various reactions,<ref>G. Dyker, ''An Eldorado for Homogeneous Catalysis?'', in ''Organic Synthesis Highlights V'', H.-G. Schmaltz, T. Wirth (eds.), pp 48–55, Wiley-VCH, Weinheim, 2003</ref> although no transformations have been commercialised. Gold(III) salts, especially [[sodium tetrachloroaurate|{{chem2|Na[AuCl4]}}]], provide an alternative to mercury(II) salts as catalysts for reactions involving alkynes. An illustrative reaction is the hydration of terminal alkynes to produce acetyl compounds.<ref>{{cite journal |author1=Y. Fukuda |author2=K. Utimoto | title = Effective transformation of unactivated alkynes into ketones or acetals with a gold(III) catalyst | journal = J. Org. Chem. | year = 1991 | volume = 56 | issue = 11 | doi = 10.1021/jo00011a058 | page = 3729}}</ref>

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Gold catalyses the alkylation of certain aromatic rings and the conversion of furans to phenols. Some alkynes undergo amination in the presence of gold(III) catalysts. For example, a mixture of acetonitrile and gold(III) chloride catalyses the alkylation of 2-methylfuran by methyl vinyl ketone at the 5-position:<ref name="tosyl"/>

:class=skin-invert-image| 450px

The efficiency of this organogold reaction is noteworthy because both the furan and the ketone are sensitive to side reactions such as polymerisation under acidic conditions. In some cases where alkynes are present, phenols sometimes form (Ts is an abbreviation for tosyl):<ref name="tosyl">{{cite journal |author1=A. S. K. Hashmi |author2=T. M. Frost |author3=J. W. Bats | title = Highly Selective Gold-Catalyzed Arene Synthesis | journal = J. Am. Chem. Soc. | year = 2000 | volume = 122 | issue = 46 | doi = 10.1021/ja005570d | pages = 11553}}</ref>

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This reaction involves a rearrangement that gives a new aromatic ring.<ref>{{cite journal |author1=A. Stephen |author2=K. Hashmi |author3=M. Rudolph |author4=J. P. Weyrauch |author5=M. Wölfle |author6=W. Frey |author7=J. W. Bats | title = Gold Catalysis: Proof of Arene Oxides as Intermediates in the Phenol Synthesis | journal = Angewandte Chemie International Edition| year = 2005 | volume = 44 | issue = 18 | doi = 10.1002/anie.200462672 | pages = 2798–801 | pmid = 15806608}}</ref>

Another example of an AuCl<sub>3</sub> catalyzed reaction is a hydroarylation, which is basically a Friedel-Crafts reaction using metal-alkyne complexes. Example, the reaction of mesitylene with phenylacetylene:<ref>{{Cite journal | doi = 10.1002/ejoc.200300260| title = Gold-Catalyzed Hydroarylation of Alkynes| journal = European Journal of Organic Chemistry| volume = 2003| issue = 18| pages = 3485–3496| year = 2003| last1 = Reetz | first1 = M. T. | last2 = Sommer | first2 = K. }}</ref>

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Gold(III) chloride can be used for the direct oxidation of primary amines into ketones, such as the oxidation of cyclohexylamine to cyclohexanone.<ref name="encyclo" /> :class=skin-invert-image| 300px This reaction is pH sensitive, requiring a mildly acidic pH to proceed, however, it does not require any additional steps.<ref name="encyclo" />

In the production of organogold(III) compounds, AuCl<sub>3</sub> is used as a source of gold. A main example of this is the production of monoarylgold(III) complexes, which are produced by direct electrophilic auration of arenes by gold(III) chloride.<ref>{{Cite journal|last1=Kharasch|first1=M. S.|last2=Isbell|first2=Horace S.|title=The Chemistry of Organic Gold Compounds. III. Direct Introduction of Gold into the Aromatic Nucleus (Preliminary Communication)|date=1931-08-01|journal=Journal of the American Chemical Society|volume=53|issue=8|pages=3053–3059|doi=10.1021/ja01359a030|issn=0002-7863}}</ref>

===Gold nanoparticles=== Gold(III) chloride is used in the synthesis of gold nanoparticles, which are extensively studied for their unique size-dependent properties and applications in fields such as electronics, optics, and biomedicine. Gold nanoparticles can be prepared by reducing gold(III) chloride with a reducing agent such as sodium tetrafluoroborate, followed by stabilization with a capping agent.<ref name="nano">{{cite journal |author1=M. Lin |author2=C. M. Sorensen |author3=K. J. Klabunde |title=Ligand-Induced Gold Nanocrystal Superlattice Formation in Colloidal Solution |journal=Chemistry of Materials |date=1999 |volume=11 |issue=2 |pages=198–202 |doi=10.1021/cm980665o |language=en}}</ref>

===Photography=== Gold(III) chloride has been used historically in the photography industry as a sensitizer in the production of photographic films and papers. However, with the advent of digital photography, its use in this field has diminished.<ref name="photo">{{cite journal |author1=Philip Ellis |title=Gold in photography |journal=Gold Bulletin |date=1975 |volume=8 |pages=7–12 |doi=10.1007/BF03215055 |s2cid=136538890 |language=en|doi-access=free }}</ref>

==Natural occurrence== This compound does not occur naturally; however, a similar compound with the formula AuO(OH,Cl)·''n''H<sub>2</sub>O is known as a product of natural gold oxidation.<ref>{{cite web |title=UM1995-16-O:AuClH |url=https://www.mindat.org/min-53581.html |website=mindat.org |access-date=27 April 2023}}</ref><ref>{{cite journal |author1=John L. Jambor |author2=Nikolai N. Pertsev |author3=Andrew C. Roberts |title=New Mineral Names |journal=American Mineralogist |date=1996 |volume=81 |page=768 |url=http://www.minsocam.org/msa/ammin/toc/Articles_Free/1996/Jambor_p766-770_96.pdf |language=en}}</ref>

==References== {{reflist}}

==External links== *{{Commons category-inline}}

{{Gold compounds}} {{Chlorides}}

Category:Chlorides Category:Metal halides Category:Gold(III) compounds Category:Deliquescent materials Category:Photographic chemicals Category:Gold–halogen compounds