| Revision as of 08:23, 25 March 2019 editLeiem (talk | contribs)Extended confirmed users, IP block exemptions2,296 edits added Category:Gold-halogen compounds using HotCat← Previous edit |
Latest revision as of 00:32, 7 November 2024 edit undoGrendon84 (talk | contribs)169 editsm Added link to goldTags: Visual edit Mobile edit Mobile web edit |
| (111 intermediate revisions by 42 users not shown) |
| Line 1: |
Line 1: |
|
{{lead too short|date=November 2016}} |
|
|
{{Chembox |
|
{{Chembox |
|
| Verifiedfields = changed |
|
|Verifiedfields = changed |
|
| Watchedfields = changed |
|
|Watchedfields = changed |
|
| verifiedrevid = 443679246 |
|
|verifiedrevid = 889373731 |
|
|
|ImageFile1 = Chloroauric acid.jpg |
|
| Name = |
|
|
|
|OtherNames = {{ubl|Hydrogen tetrachloroaurate|Hydrogen tetrachloroaurate(III)|Chlorauric acid|Tetrachloroauric(III) acid|Aurochloric acid|Aurate(1−), tetrachloro-, hydrogen, (SP-4-1)-|Hydrogen aurichloride|brown gold chloride}} |
|
| ImageFile = |
|
|
|
|Section1 = {{Chembox Identifiers |
|
| ImageFile1 = ] |
|
|
|
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
| IUPACName = |
|
|
|
|ChemSpiderID = 26171 |
|
| OtherNames = Hydrogen tetrachloroaurate,<br/>Chlorauric acid,<br/>Aurochloric acid,<br/>Aurate(1−), tetrachloro-, hydrogen, (SP-4-1)-,<br/>Hydrogen aurichloride |
|
|
|
|InChI = 1/Au.4ClH.Na/h;4*1H;/q+3;;;;;+1/p-4/rAuCl4.Na/c2-1(3,4)5;/q-1;+1 |
|
| SystematicName = |
|
|
|
|InChIKey = IXPWAPCEBHEFOV-ACHCXQQJAP |
|
| Section1 = {{Chembox Identifiers |
|
|
|
|InChI1 = 1/Au.4ClH/h;4*1H/q+3;;;;/p-3/rAuCl4/c2-1(3,4)5/q-1/p+1 |
|
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
|
|
|InChIKey1 = VDLSFRRYNGEBEJ-ZXMCYSOYAI |
|
| ChemSpiderID = 26171 |
|
|
|
|StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
|
| InChI = 1/Au.4ClH.Na/h;4*1H;/q+3;;;;;+1/p-4/rAuCl4.Na/c2-1(3,4)5;/q-1;+1 |
|
|
|
|StdInChI = 1S/Au.4ClH/h;4*1H/q+3;;;;/p-3 |
|
| InChIKey = IXPWAPCEBHEFOV-ACHCXQQJAP |
|
|
|
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
|
| InChI1 = 1/Au.4ClH/h;4*1H/q+3;;;;/p-3/rAuCl4/c2-1(3,4)5/q-1/p+1 |
|
|
| InChIKey1 = VDLSFRRYNGEBEJ-ZXMCYSOYAI |
|
|StdInChIKey = VDLSFRRYNGEBEJ-UHFFFAOYSA-K |
|
|
|CASNo = 16903-35-8 |
|
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
|
|
|
|CASNo_Ref = {{cascite|correct|CAS}} |
|
| StdInChI = 1S/Au.4ClH/h;4*1H/q+3;;;;/p-3 |
|
|
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
|
|CASNo2_Ref = {{cascite|correct|CAS}} |
|
|
|CASNo2 = 16961-25-4 |
|
| StdInChIKey = VDLSFRRYNGEBEJ-UHFFFAOYSA-K |
|
|
|
|CASNo2_Comment = (trihydrate) |
|
| CASNo = 16903-35-8 |
|
|
| CASNo_Ref = {{cascite|correct|CAS}} |
|
|UNII_Ref = {{fdacite|correct|FDA}} |
|
|
|UNII = 8H372EGX3V |
|
| CASNo2_Ref = {{cascite|changed|??}} |
|
|
|
|UNII2 = 31KV0KH4AY |
|
| CASNo2 = 16961-25-4 |
|
|
|
|UNII2_Ref = {{fdacite|correct|FDA}} |
|
| CASNo2_Comment = (trihydrate) |
|
|
|
|UNII2_Comment = (trihydrate) |
|
| PubChem = 28133 |
|
|
|
|PubChem = 28133 |
|
| SMILES = .Cl(Cl)(Cl)Cl |
|
|
|
|EINECS = 240-948-4 |
|
}} |
|
|
|
|SMILES = .Cl(Cl)(Cl)Cl |
|
| Section2 = {{Chembox Properties |
|
|
|
}} |
|
| Formula = HAuCl<sub>4</sub> |
|
|
|
|Section2 = {{Chembox Properties |
|
| MolarMass = 339.785 g/mol (anhydrous) <br> 393.833 g/mol (trihydrate)<br> 411.85 g/mol (tetrahydrate) |
|
|
|
|Formula = {{chem2|H}} |
|
| Appearance = orange-yellow needle-like crystals <br> ] |
|
|
| Density = 3.9 g/cm<sup>3</sup> (anhydrous) <br> 2.89 g/cm<sup>3</sup> (tetrahydrate) |
|
|MolarMass = {{ubl|339.785 g/mol (anhydrous)|393.833 g/mol (trihydrate)|411.85 g/mol (tetrahydrate)}} |
|
|
|ConjugateBase = Tetrachloroaurate(III) |
|
| MeltingPtC = 254 |
|
|
|
|Appearance = orange-yellow needle-like ] crystals |
|
| MeltingPt_notes = (decomposes) |
|
|
| Solubility = 350 g HAuCl<sub>4</sub> / 100 g H<sub>2</sub>O |
|
|Density = 3.9 g/cm<sup>3</sup> (anhydrous)<br>2.89 g/cm<sup>3</sup> (tetrahydrate) |
|
|
|MeltingPtC = 254 |
|
| SolubleOther = soluble in ], ], ], ] |
|
|
|
|MeltingPt_notes = (decomposes) |
|
| LogP =2.67510 <ref name="chemsrc">{{Cite web|url=https://www.chemsrc.com/en/cas/16961-25-4_829290.html|title=hydrogen tetrachloroaurate(iii)_msds}}</ref> |
|
|
|
|Solubility = 350 g of {{chem2|H}} in 100 g of {{chem2|H2O}} |
|
}} |
|
|
|
|SolubleOther = soluble in ], ], ], ] |
|
| Section3 = {{Chembox Structure |
|
|
|
|LogP =2.67510 <ref name="chemsrc">{{Cite web|url=https://www.chemsrc.com/en/cas/16961-25-4_829290.html|title=hydrogen tetrachloroaurate(iii)_msds}}</ref> |
|
| CrystalStruct = monoclinic |
|
|
}} |
|
}} |
|
| Section4 = {{Chembox Hazards |
|
|Section3 = {{Chembox Structure |
|
|
|CrystalStruct = monoclinic |
|
| ExternalSDS = |
|
|
|
}} |
|
| EUClass = not listed |
|
|
|
|Section4 = {{Chembox Hazards |
|
| FlashPt = |
|
|
|
|ExternalSDS = |
|
| NFPA-H=3 |
|
|
|
|GHSPictograms = {{GHS05}}{{GHS07}}{{GHS08}}{{GHS09}} |
|
| NFPA-F=0 |
|
|
|
|GHSSignalWord = Danger |
|
| NFPA-R=1 |
|
|
|
|HPhrases = {{H-phrases|302|314|317|373|411}} |
|
| AutoignitionPt = |
|
|
|
|PPhrases = {{P-phrases|260|261|264|272|280|301+330+331|302+352|303+361+353|304+340|305+351+338|310|321|333+313|363|405|501}} |
|
}} |
|
|
|
|NFPA-H=3 |
|
| Section5 = |
|
|
|
|NFPA-F=0 |
|
| Section6 = {{Chembox Related |
|
|
|
|NFPA-R=1 |
|
| OtherAnions = ] |
|
|
}} |
|
}} |
|
|
|Section6 = {{Chembox Related |
|
|
|OtherAnions = ] |
|
|
|OtherCompounds = ] |
|
|
}} |
|
}} |
|
}} |
|
|
|
|
|
'''Chloroauric acid''' is an ] with the ] {{Chem|HAuCl|4}}. Both the trihydrate and tetrahydrate are known. It is an orange-yellow solid, a common precursor to other ] compounds and an intermediate in the purification of gold metal. Both the trihydrate and tetrahydrate are available commercially. |
|
'''Chloroauric acid''' is an ] with the ] {{chem2|H}}. It forms hydrates {{chem2|H*''n''H2O}}. Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar {{chem2|−}} anion. Often chloroauric acid is handled as a solution, such as those obtained by dissolution of ] in ]. These solutions can be converted to other gold complexes or reduced to metallic gold or ]. |
|
|
|
|
== Chemical properties == |
|
|
=== Acidity === |
|
|
Chloroauric acid is a strong ] acid. |
|
|
|
|
|
|
|
== Properties == |
|
|
The tetrahydrate crystallizes as {{chem2|+−}} and two water molecules.<ref name="WilliamsPeterson1969">{{cite journal|last1=Williams|first1=Jack Marvin|last2=Peterson|first2=Selmer Wiefred|title=Example of the <sup>+</sup> ion. Neutron diffraction study of tetrachloroauric acid tetrahydrate|journal=Journal of the American Chemical Society|volume=91|issue=3|year=1969|pages=776–777|issn=0002-7863|doi=10.1021/ja01031a062}}</ref><ref>{{cite journal |doi=10.1063/1.1675731 |title=Nuclear Magnetic Resonance of the Aquated Proton. II. Chloroauric Acid Tetrahydrate. Phase Transitions and Molecular Motion |date=1971 |last1=O'Reilly |first1=Donald E. |last2=Peterson |first2=E. M. |last3=Scheie |first3=C. E. |last4=Williams |first4=Jack M. |journal=The Journal of Chemical Physics |volume=55 |issue=12 |pages=5629–5635 |bibcode=1971JChPh..55.5629O }}</ref> |
|
=== Structure === |
|
=== Structure === |
|
|
The oxidation state of gold in {{chem2|H}} and {{chem2|−}} anion is +3. The salts of {{chem2|H}} (tetrachloroauric(III) acid) are tetrachloroaurates(III), containing {{chem2|−}} anions (tetrachloroaurate(III) anions), which have ]. The Au–Cl distances are around 2.28 Å. Other d<sup>8</sup> complexes adopt similar structures, e.g. tetrachloroplatinate(II) (2−)}}]]. |
|
The crystalline tetrahydrate is known to contain {{chem|H|5|O|2|+}}·{{chem|AuCl|4|−}} and two water molecules.<ref name="WilliamsPeterson1969">{{cite journal|last1=Williams|first1=Jack Marvin|last2=Peterson|first2=Selmer Wiefred|title=Example of the <sup>+</sup> ion. Neutron diffraction study of tetrachloroauric acid tetrahydrate|journal=Journal of the American Chemical Society|volume=91|issue=3|year=1969|pages=776–777|issn=0002-7863|doi=10.1021/ja01031a062}}</ref> |
|
|
The {{chem|AuCl|4|−}} anion has ]. The Au–Cl distances are around 2.28 Å. Other d<sup>8</sup> complexes adopt similar structures, e.g. <sup>2−</sup>. |
|
|
|
|
|
|
=== Solute properties === |
|
=== Solute properties === |
|
] chloroauric acid is a ] (]) ]. It is soluble not only in water, but also in many oxygen-containing solvents, such as alcohols, esters, ethers, and ketones. For example, in dry dibutyl ether of ], the solubility exceeds 1 mol/L.{{citation needed|date=January 2014}} Saturated solutions in the organic solvents often are the liquid solvates of specific stoichiometry. |
|
] chloroauric acid is a ] (]) ]. It is soluble in water and other oxygen-containing solvents, such as alcohols, esters, ethers, and ketones. For example, in dry ] or ], the solubility exceeds 1 M.<ref name="Extractant" /><ref name='minataur' /><ref name ="Morris" /> Saturated solutions in the organic solvents often are the liquid solvates of specific stoichiometry. Chloroauric acid is a strong ] acid. |
|
|
|
|
|
When heated in air, solid HAuCl<sub>4</sub>·{{mvar|n}}H<sub>2</sub>O melts in the water of crystallization, quickly darkens and becomes dark brown. |
|
When heated in air, solid {{chem2|H*''n''H2O}} melts in the water of crystallization, quickly darkens and becomes dark brown. |
|
|
|
|
|
=== Chemical reactions === |
|
=== Chemical reactions === |
|
Upon treating chloroauric acid with a standard base, it converts to metal, tetrachloridoaurate and ]. The related thallium{{clarify|date=December 2016}} salt is poorly soluble in all nonreacting solvents. Salts of ]s are known.<ref name="solidcontact">{{Cite journal | last1 = Makotchenko | first1 = E. V. | last2 = Kokovkin | first2 = V. V. | doi = 10.1134/S1070363210090021 | title = Solid contact <sup>−</sup>-selective electrode and its application for evaluation of gold(III) in solutions| journal = Russian Journal of General Chemistry | volume = 80 | issue = 9 | pages = 1733 | year = 2010 | pmid = | pmc = }}</ref> Other complex salts include <ref name="x13" >{{cite journal|last=Mironov|first=I. V.|last2=Tsvelodub|first2=L. D.|title=Equilibria of the substitution of pyridine, 2,2′-bipyridyl, and 1,10-phenanthroline for Cl<sup>−</sup> in AuCl<sub>4</sub><sup>−</sup> in aqueous solution|journal=Russian Journal of Inorganic Chemistry|date=2001|volume=46|pages=143–148}}</ref> and Cl<sub>2</sub>. |
|
Since {{chem2|−}} is prone to hydrolyze,<ref>{{cite journal | last1=Đurović | first1=Mirjana D. | last2=Puchta | first2=Ralph | last3=Bugarčić | first3=Živadin D. | last4=Eldik | first4=Rudi van | title=Studies on the reactions of [AuCl<sub>4</sub>]<sup>−</sup> with different nucleophiles in aqueous solution | journal=Dalton Transactions | volume=43 | issue=23 | date=1999-02-22 | doi=10.1039/C4DT00247D | pages=8620–8632 | pmid=24760299 | doi-access=free }}</ref> upon treatment with an alkali metal base, chloroauric acid converts to ].<ref>{{cite journal | last1=Kawamoto | first1=Daisuke | last2=Ando | first2=Hiroaki | last3=Ohashi | first3=Hironori | last4=Kobayashi | first4=Yasuhiro | last5=Honma | first5=Tetsuo | last6=Ishida | first6=Tamao | last7=Tokunaga | first7=Makoto | last8=Okaue | first8=Yoshihiro | last9=Utsunomiya | first9=Satoshi | last10=Yokoyama | first10=Takushi | title=Structure of a Gold(III) Hydroxide and Determination of Its Solubility | journal=Bulletin of the Chemical Society of Japan | publisher=The Chemical Society of Japan | volume=89 | issue=11 | date=2016-11-15 | issn=0009-2673 | doi=10.1246/bcsj.20160228 | pages=1385–1390| doi-access=free }}</ref> The related thallium salt({{chem2|Tl+-}}) is poorly soluble in all nonreacting solvents. Salts of ]s are known.<ref name="solidcontact">{{Cite journal | last1 = Makotchenko | first1 = E. V. | last2 = Kokovkin | first2 = V. V. | doi = 10.1134/S1070363210090021 | title = Solid contact <sup>−</sup>-selective electrode and its application for evaluation of gold(III) in solutions| journal = Russian Journal of General Chemistry | volume = 80 | issue = 9 | pages = 1733 | year = 2010 | s2cid = 95581984 }}</ref> Other complex salts include {{chem2|])Cl2]+-}}<ref name="x13" >{{cite journal|last1=Mironov|first1=I. V.|last2=Tsvelodub|first2=L. D.|title=Equilibria of the substitution of pyridine, 2,2′-bipyridyl, and 1,10-phenanthroline for Cl<sup>−</sup> in AuCl<sub>4</sub><sup>−</sup> in aqueous solution|journal=Russian Journal of Inorganic Chemistry|date=2001|volume=46|pages=143–148}}</ref> and {{chem2|(3+)-(Cl-)2}}. |
|
|
|
|
|
|
Partial reduction of chloroauric acid gives oxonium dichloridoaurate(1−).<ref name="Huang2010">{{Cite journal|last1=Huang|first1=Xiaohua|last2=Peng|first2=Xianghong|last3=Wang|first3=Yiqing|first4=Yuxiang|last4=Wang|last5=Shin|first5=Dong M.|last6=El-Sayed|first6=Mostafa A.|last7=Nie|first7=Shuming |title=A reexamination of active and passive tumor targeting by using rod-shaped gold nanocrystals and covalently conjugated peptide ligands|journal=ACS Nano|date=26 October 2010|volume=4|issue=10|pages=5887–5896|doi=10.1021/nn102055s|publisher=ACS Publications|pmc=2964428|pmid=20863096}}</ref> Reduction may also yield other gold(I) complexes, especially with organic ligands. Often the ligand serves as reducing agent as illustrated with ], {{chem2|CS(NH2)2}}: |
|
Gold nanostructures can be made from chloroauric acid in a two-phase redox reaction whereby metallic clusters are amassed through the simultaneous attachment of self-assembled thiol monolayers on the growing nuclei. {{chem|AuCl|4|−}} is transferred from aqueous solution to toluene using tetraoctylammonium bromide where it is then reduced with aqueous sodium borohydride in the presence of a thiol.<ref name=Brust1994>{{Cite journal|last=Brust|first=Mathias|last2=Walker|first2=Merryl|last3=Bethell|first3=Donald|last4=Schiffrin|first4=David J.|last5=Whyman|first5=Robin |title=Synthesis of Thiol-derivatised Gold Nanoparticles in a Two-phase Liquid-Liquid System|journal=J. Chem. Soc., Chem. Commun.|date=1994|issue=7|pages=801–802|doi=10.1039/C39940000801|publisher=Royal Society of Chemistry}}</ref> |
|
|
|
:{{chem2|- + 3 CS(NH2)2 + H2O → + + CO(NH2)2 + S + 2 Cl- + 2 HCl}} |
|
|
|
|
|
|
Chloroauric acid is the precursor to gold nanoparticles by precipitation onto mineral supports.<ref>{{Cite journal | last1 = Gunanathan | first1 = C. | last2 = Ben-David | first2 = Y. | last3 = Milstein | first3 = D. | doi = 10.1126/science.1145295 | title = Direct Synthesis of Amides from Alcohols and Amines with Liberation of H<sub>2</sub> | journal = Science | volume = 317 | issue = 5839 | pages = 790–792 | year = 2007 | pmid = 17690291| bibcode = 2007Sci...317..790G | s2cid = 43671648 }}</ref> Heating of {{chem2|H*''n''H2O}} in a stream of chlorine gives ] ({{chem2|Au2Cl6}}).<ref name="x5">{{cite book|last= Mellor|first= J. W. |author-link=Joseph Mellor|title=A Comprehensive Treatise on Inorganic and Theoretical Chemistry |url= https://archive.org/details/b2980789x_0016|date=1946|at=vol. 3, p. 593}}</ref> Gold nanostructures can be made from chloroauric acid in a two-phase redox reaction whereby metallic clusters are amassed through the simultaneous attachment of self-assembled thiol monolayers on the growing nuclei. {{chem2|−}} is transferred from aqueous solution to toluene using tetraoctylammonium bromide where it is then reduced with aqueous sodium borohydride in the presence of a thiol.<ref name="Brust1994">{{Cite journal|last1=Brust|first1=Mathias|last2=Walker|first2=Merryl|last3=Bethell|first3=Donald|last4=Schiffrin|first4=David J.|last5=Whyman|first5=Robin |title=Synthesis of Thiol-derivatised Gold Nanoparticles in a Two-phase Liquid-Liquid System|journal=J. Chem. Soc., Chem. Commun.|date=1994|issue=7|pages=801–802|doi=10.1039/C39940000801|publisher=Royal Society of Chemistry}}</ref> |
|
Partial reduction of chloroauric acid gives oxonium dichloridoaurate(1−).<ref name=Huang2010>{{Cite journal|last=Huang|first=Xiaohua|last2=Peng|first2=Xianghong|last3=Wang|first3=Yiqing|first4=Yuxiang|last4=Wang|last5=Shin|first5=Dong M.|last6=El-Sayed|first6=Mostafa A.|last7=Nie|first7=Shuming |title=A reexamination of active and passive tumor targeting by using rod-shaped gold nanocrystals and covalently conjugated peptide ligands|journal=ACS Nano|date=26 October 2010|volume=4|issue=10|pages=5887–5896|doi=10.1021/nn102055s|publisher=ACS Publications|pmc=2964428}}</ref> Reduction may also yield other gold(I) complexes, especially with organic ligands. Often the ligand serves as reducing agent as illustrated with ], (H<sub>2</sub>N)<sub>2</sub>CS: |
|
|
:{{chem|AuCl|4|−}} + 4 {{chem|(H|2|N)|2|CS}} + {{chem|H|2|O}} → {{chem|Au|2|+}} + {{chem|(H|2|N)|2|CO}} + S + 2 {{chem|Cl|−}} + 2 HCl |
|
|
|
|
|
Chloroauric acid is the precursor to gold nanoparticles by precipitation onto mineral supports.<ref>{{Cite journal | last1 = Gunanathan | first1 = C. | last2 = Ben-David | first2 = Y. | last3 = Milstein | first3 = D. | doi = 10.1126/science.1145295 | title = Direct Synthesis of Amides from Alcohols and Amines with Liberation of H<sub>2</sub> | journal = Science | volume = 317 | issue = 5839 | pages = 790–792 | year = 2007 | pmid = 17690291| pmc = }}</ref> |
|
|
Heating of HAuCl<sub>4</sub>·{{mvar|n}}H<sub>2</sub>O in a stream of chlorine gives ] (Au<sub>2</sub>Cl<sub>6</sub>).<ref name="x5">{{cite book|last= Mellor|first= J. W. |title=A Comprehensive Treatise on Inorganic and Theoretical Chemistry |date=1946|at=vol. 3, p. 593}}</ref> |
|
|
|
|
|
|
== Production == |
|
== Production == |
|
Chloroauric acid is produced by dissolving gold in ] (a mixture of concentrated ] and ]s) followed by careful evaporation of the solution:<ref>{{cite book|title=Handbook of Preparative Inorganic Chemistry |edition=2nd |editor-first=G. |editor-last=Brauer |publisher=Academic Press |date=1963 |location=New York}}</ref> |
|
Chloroauric acid is produced by dissolving gold in ] (a mixture of concentrated ] and ] acids) followed by careful evaporation of the solution:<ref>{{cite book|title=Handbook of Preparative Inorganic Chemistry |edition=2nd |editor-first=G. |editor-last=Brauer |publisher=Academic Press |date=1963 |location=New York}}</ref><ref>{{cite book |doi=10.1002/9780470132357.ch4|chapter=Gold Powder and Potassium Tetrabromoaurate(III)|year=1953|volume=4|last1=Block|first1=B. P.|title=Inorganic Syntheses|pages=14–17|isbn=9780470132357}}</ref> |
|
:Au + HNO<sub>3</sub> + 4 HCl → HAuCl<sub>4</sub> + ] + 2 H<sub>2</sub>O |
|
:{{chem2|Au(s) + HNO3(aq) + 4 HCl(aq) → H(aq) + NO(g) + 2 H2O(l)}} |
|
Under some conditions, oxygen can be used as the oxidant.<ref>{{cite journal|last1=Novoselov |first1=R. I. |last2=Makotchenko |first2=E. V. |title=Application of oxygen as ecologically pure reagent for the oxidizing of non-ferrous and precious metals, sulphide minerals |journal=Chemistry for Sustainable Development |date=1999 |volume= 7 |pages= 321–330}}</ref> For higher efficiency, these processes are conducted in autoclaves, which allows greater control of temperature and pressure. Alternatively, a solution of HAuCl<sub>4</sub> can be produced by electrolysis of gold metal in ]: |
|
Under some conditions, oxygen can be used as an oxidant.<ref>{{cite journal|last1=Novoselov |first1=R. I. |last2=Makotchenko |first2=E. V. |title=Application of oxygen as ecologically pure reagent for the oxidizing of non-ferrous and precious metals, sulphide minerals |journal=Chemistry for Sustainable Development |date=1999 |volume= 7 |pages= 321–330}}</ref> For higher efficiency, these processes are conducted in ]s, which allows greater control of temperature and pressure. Alternatively, a solution of {{chem2|H}} can be produced by electrolysis of gold metal in ]: |
|
:2 Au + 8 HCl → 2 HAuCl<sub>4</sub> + 3H<sub>2</sub> |
|
:{{chem2|2 Au(s) + 8 HCl(aq) → 2 H(aq) + 3 H2(g)}} |
|
|
|
|
|
To prevent the ] of gold on the cathode, the electrolysis is carried out in a cell equipped with a membrane. This method is used for refining gold. Some gold remains in solution in the form of <sup>−</sup>.<ref name="x4">{{cite journal|last=Belevantsev |first=V. I. |last2=Peschevitskii |first2=B. I. |last3=Zemskov |first3=S. V. |title=New data on chemistry of gold compounds in solutions |journal=Izvestiya Sibirskogo Otdeleniya AN SSSR, Ser. Khim. Nauk. |date=1976 |volume=4 |issue=2 |pages= 24–45}}</ref> |
|
To prevent the ] of gold on the cathode, the electrolysis is carried out in a cell equipped with a membrane. This method is used for refining gold. Some gold remains in solution in the form of {{chem2|−}}.<ref name="x4">{{cite journal|last1=Belevantsev |first1=V. I. |last2=Peschevitskii |first2=B. I. |last3=Zemskov |first3=S. V. |title=New data on chemistry of gold compounds in solutions |journal=Izvestiya Sibirskogo Otdeleniya AN SSSR, Ser. Khim. Nauk. |date=1976 |volume=4 |issue=2 |pages= 24–45}}</ref> |
|
|
|
|
A solution of HAuCl<sub>4</sub> can also be obtained by the action of ] or chlorine water on metallic gold in hydrochloric acid: |
|
|
:2 Au + 3 Cl<sub>2</sub> + 2 HCl → 2 HAuCl<sub>4</sub> |
|
|
This reaction is widely used for extracting gold from electronic and other "rich" materials. |
|
|
|
|
|
In addition to the above routes, many other ways exist to dissolve gold, differing in the choice of the oxidant (hydrogen peroxide, hypochlorites) or variations of conditions. It is possible also to convert the trichloride (Au<sub>2</sub>Cl<sub>6</sub>) or the oxide (Au<sub>2</sub>O<sub>3</sub>·{{mvar|n}}H<sub>2</sub>O). |
|
|
|
|
|
|
== Uses == |
|
== Uses == |
|
Chloroauric acid is the precursor used in the purification of gold by ]. |
|
Chloroauric acid is the precursor used in the ] by ]. |
|
|
|
|
|
Liquid–liquid extraction of chloroauric acid is used for the recovery, concentrating, purification, and analytical determinations of gold. Of great importance is the extraction of {{chem2|H}} from hydrochloric medium by oxygen-containing extractants, such as alcohols, ketones, ethers and esters. The concentration of gold(III) in the extracts may exceed 1 mol/L.<ref name="Extractant">{{Cite journal | last1 = Mironov | first1 = I. V. | last2 = Natorkhina | first2 = K. I. | doi = 10.1134/S0036023612040195 | title = On the selection of extractant for the preparation of high-purity gold | journal = Russian Journal of Inorganic Chemistry | volume = 57 | issue = 4 | pages = 610 | year = 2012 | s2cid = 98015888 }}</ref><ref name='minataur'>{{cite journal | title = Gold refining by solvent extraction—the minataur process | journal = Journal of the Southern African Institute of Mining and Metallurgy | date = July 1997 | first1 = A. | last1 = Feather |first2=K. C. |last2=Sole |first3=L. J. |last3=Bryson | pages = 169–173 | url = http://www.saimm.co.za/Journal/v097n04p169.pdf | access-date = 2013-03-17}}</ref><ref name ="Morris">{{cite journal|last1=Morris |first1=D. F. C. |last2=Khan |first2=M. A. |title=Application of solvent extraction to the refining of precious metals, Part 3: purification of gold |journal=Talanta |date=1968 |volume=15 |issue=11 |pages=1301–1305 |doi=10.1016/0039-9140(68)80053-0|pmid=18960433 }}</ref> Frequently used extractants for this purpose are dibutyl glycol, ], ], ] (chlorex).<ref name = "Hill_Lear_1988">{{cite journal |vauthors = Hill JW, Lear TA|title=Recovery of gold from electronic scrap|journal = J. Chem. Educ.|date = September 1988|volume=65|issue=9|page=802|doi=10.1021/ed065p802|bibcode=1988JChEd..65..802H}}</ref> |
|
|
|
|
|
|
In ], chlorauric acid is known as "brown gold chloride", and its sodium salt {{chem2|Na}} (]) as "gold chloride", "sodium gold chloride" or "yellow gold chloride". The sodium salt is used in a process called "toning" to improve the optical definition of tissue sections ].<ref>{{cite web |url=http://stainsfile.info/StainsFile//stain/metallic/impregnate.htm |title=Silver Impregnation |access-date=April 14, 2016 |archive-url=https://web.archive.org/web/20160421042407/http://stainsfile.info/StainsFile/stain/metallic/impregnate.htm |archive-date=April 21, 2016 |url-status=dead }}</ref> |
|
Liquid–liquid extraction of chloroauric acid is used for the recovery, concentrating, purification, and analytical determinations of gold. Of great importance is the extraction of HAuCl<sub>4</sub> from hydrochloric medium by oxygen-containing extractants, such as alcohols, ketones, ethers and esters. The concentration of gold(III) in the extracts may exceed 1 mol/L.<ref name="Extractant">{{Cite journal | last1 = Mironov | first1 = I. V. | last2 = Natorkhina | first2 = K. I. | doi = 10.1134/S0036023612040195 | title = On the selection of extractant for the preparation of high-purity gold | journal = Russian Journal of Inorganic Chemistry | volume = 57 | issue = 4 | pages = 610 | year = 2012 | pmid = | pmc = }}</ref><ref name='minataur'>{{cite journal | title = Gold refining by solvent extraction—the minataur™ process | journal = Journal of the Southern African Institute of Mining and Metallurgy | date = July 1997 | first = A. | last = Feather |first2=K. C. |last2=Sole |first3=L. J. |last3=Bryson | pages = 169–173 | url = http://www.saimm.co.za/Journal/v097n04p169.pdf | format = PDF | accessdate = 2013-03-17}}</ref><ref>{{cite journal|last1=Morris |first1=D. F. C. |last2=Khan |first2=M. A. |title=Application of solvent extraction to the refining of precious metals, Part 3: purification of gold |journal=Talanta |date=1968 |volume=15 |pages=1301–1305 |doi=10.1016/0039-9140(68)80053-0}}</ref> The most frequently used extractants for this purpose are dibutyl glycol, ], ], dichlorodiethyl ether (chlorex). |
|
|
|
|
|
|
|
In ], chlorauric acid can be used as a ].<ref>{{Cite web |title=Chloroauric Acid |url=https://www.chm.bris.ac.uk/motm/chloroauric-acid/Chloroauric%20Acid.htm |website=Shahjalal Science & Technology University}}</ref> |
|
In ], chlorauric acid is known as "brown gold chloride", and its sodium salt NaAuCl<sub>4</sub> as "gold chloride", "sodium gold chloride" or "yellow gold chloride". The sodium salt is used in a process called "toning" to improve the optical definition of tissue sections ].<ref>{{cite web |url=http://stainsfile.info/StainsFile//stain/metallic/impregnate.htm |title=Silver Impregnation |accessdate=April 14, 2016}}</ref> |
|
|
|
|
|
|
== Health effects and safety == |
|
== Health effects and safety == |
|
Chloroauric acid is a strong eye, skin, and mucous membrane irritant. Prolonged skin contact with chloroauric acid may result in tissue destruction. Concentrated chloroauric acid is ] to skin and must, therefore, be handled with appropriate care, since it can cause skin burns, permanent eye damage, and irritation to mucous membranes. Gloves are worn when handling the compound. It can stain skin purple for several days after contact. |
|
Chloroauric acid is a strong eye, skin, and mucous membrane irritant. Prolonged skin contact with chloroauric acid may result in tissue destruction. Concentrated chloroauric acid is ] to skin and must, therefore, be handled with appropriate care, since it can cause skin burns, permanent eye damage, and irritation to mucous membranes. Gloves are worn when handling the compound.{{citation needed|date=May 2023}} |
|
|
|
|
|
== References == |
|
== References == |
| Line 113: |
Line 106: |
|
{{Gold compounds}} |
|
{{Gold compounds}} |
|
|
|
|
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |