Gold(III) chloride
General
Systematic name	Gold(III) chloride
Other names	Auric chloride Gold trichloride
Molecular formula	AuCl3 (exists as Au2Cl6)
Molar mass	303.33 g/mol (anhydrous)
Appearance	Red crystalline solid
CAS number	[13453-07-1]
Properties
Density and phase	3.9 g/cm3 (solid)
Solubility in water	68 g/100 ml (cold)
ethanol, diethyl ether	soluble
Melting point	254 °C (527 K) (decomposes)
Structure
Coordination geometry	Square planar
Crystal structure	?
Hazards
MSDS	External MSDS
Main hazards	irritant
NFPA 704	Estimated
R/S statement	R: 36/37/38 S: 26-36
RTECS number	MD5420000 (anhydrous)
Supplementary data page
Structure & properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other anions	Gold(III) fluoride Gold(III) bromide
Other cations	Gold(I) chloride Silver(I) chloride Platinum(II) chloride Mercury(II) chloride
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references

Gold(III) chloride, traditionally called auric chloride, is one of the most common compounds of gold. It has the formula AuCl₃. The Roman numerals in the name indicate that the gold has an oxidation state of +3, which is the most stable form for gold in its compounds. Gold also forms another chloride, gold(I) chloride (AuCl) which is less stable than AuCl₃. Also chlorauric acid (HAuCl₄), the product formed when gold dissolves in aqua regia, is sometimes referred to rather loosely as "gold chloride", "acid gold trichloride" or even "gold(III) chloride trihydrate". Image File history File links Concentrated aqueous solution of gold(III) chloride (auric chloride) Picture taken ca. ... IUPAC nomenclature is a systematic way of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of an element or chemical compound. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... A substance is soluble in a fluid if it dissolves in the fluid. ... Water is in dynamic equilibrium between the liquid and solid states at standard temperature and pressure. ... Ethyl alcohol, also known as ethanol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... Diethyl ether, also known as ether and ethoxyethane, is a clear, colorless, and highly flammable liquid with a low boiling point and a typical smell. ... The melting point of a solid is the temperature at which it changes state from solid to liquid. ... Rose des Sables (Sand Rose), a formation of gypse crystal In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... A material safety data sheet or MSDS is a form containing data regarding the properties of a particular substance. ... This page provides supplementary chemical data on gold(III) chloride // Thermodynamic properties Spectral data Structure and properties data Material Safety Data Sheet The handling of this chemical may incur notable safety precautions. ... Worker safety and health is the prevention and reduction of the number of occupational safety and health hazards at the places of employment, providing safe and healthful working conditions. ... NFPA 704 is a standard maintained by the National Fire Protection Association. ... Image File history File links File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Risk and Safety Statements, also known as R/S statements, R/S numbers, R/S phrases, and R/S sentences, is a system of hazard codes and phrases for labeling dangerous chemicals and compounds. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... This page provides supplementary chemical data on gold(III) chloride // Thermodynamic properties Spectral data Structure and properties data Material Safety Data Sheet The handling of this chemical may incur notable safety precautions. ... This page provides supplementary chemical data on gold(III) chloride // Thermodynamic properties Spectral data Structure and properties data Material Safety Data Sheet The handling of this chemical may incur notable safety precautions. ... The refractive index of a material is the factor by which electromagnetic radiation is slowed down (relative to vacuum) when it travels inside the material. ... The dielectric constant εr (represented as or K in some cases) is defined as the ratio: where εs is the static permittivity of the material in question, and ε0 is the vacuum permittivity. ... This page provides supplementary chemical data on gold(III) chloride // Thermodynamic properties Spectral data Structure and properties data Material Safety Data Sheet The handling of this chemical may incur notable safety precautions. ... This page provides supplementary chemical data on gold(III) chloride // Thermodynamic properties Spectral data Structure and properties data Material Safety Data Sheet The handling of this chemical may incur notable safety precautions. ... Ultraviolet-Visible spectroscopy or Ultraviolet-Visible spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... IR spectrum of a thin film of liquid ethanol. ... Nuclear Magnetic Resonance Spectroscopy is the name given to the technique which exploits the magnetic properties of nuclei. ... Mass spectrometry is a technique for separating ions by their mass-to-charge (m/z) ratios. ... An ion is an elementary particle or system of elementary particles with a net electric charge. ... An ion is an elementary particle or system of elementary particles with a net electric charge. ... Silver chloride (also called silver(I) chloride) is a chemical compound with chemical formula AgCl. ... Mercury(II) chloride (also called mercuric chloride and corrosive sublimate) is a poisonous white soluble crystalline sublimate of mercury. ... In chemistry, the standard state of a material is its state at 1 bar (100. ... An inorganic compound is a chemical compound not containing carbon and hydrogen atoms bonded to each other. ... General Name, Symbol, Number Gold, Au, 79 Chemical series transition metals Group, Period, Block 11 (IB), 6, d Density, Hardness 19300 kg/m3, 2. ... General Name, Symbol, Number Gold, Au, 79 Chemical series transition metals Group, Period, Block 11 (IB), 6, d Density, Hardness 19300 kg/m3, 2. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... The oxidation state or oxidation number is defined as the sum of negative and positive charges in an atom, which indirectly indicates the number of electrons it has accepted or donated. ... The chloride ion is formed when the element chlorine picks up one electron to form the anion (negatively charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and are also called chlorides. ... Aqua regia (Latin for royal water) is a highly corrosive, fuming yellow liquid, formed by a fresh mixture of concentrated nitric acid (otherwise known as aqua fortis) and concentrated hydrochloric acid, usually in the ratio of one to three. ...

Gold(III) chloride is very hygroscopic and highly soluble in water and ethanol. It decomposes above 160 °C or in light, and it readily forms complexes with ligands. A hygroscopic or hydroscopic substance is a substance that absorbs water readily from its surroundings. ... Ethyl alcohol, also known as ethanol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... A complex in chemistry and biochemistry is a reversible association of molecules, atoms, or ions through weak non-covalent chemical bonds. ... In chemistry, a ligand is an atom, ion or functional group that is bonded to one or more central atoms or ions, usually metals generally through co-ordinate covalent bond. ...

Structure

Image File history File links The structure of w:gold(III) chloride in the solid state. ...

AuCl₃ exists as a dimer both as a solid and as a vapour; the bromide AuBr₃ follows the same pattern. This is similar (but not identical) to the tetrahedral dimers formed by AlCl₃ and FeCl₃. The bonding in AuCl₃ is mainly covalent, reflecting the high oxidation state and relatively high electronegativity (for a metal) of the gold. A tetrahedron (plural: tetrahedra) is a polyhedron composed of four triangular faces, three of which meet at each vertex. ... Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. ... Iron(III) chloride, generically called ferric chloride, is an iron-based salt of chemical formula FeCl3. ... Covalently bonded hydrogen and carbon in a molecule of methane. ... Electronegativity is the measure of the ability of an atom or a molecule to attract a pair of electrons in a covalent bond. ...

Chemical properties

Anhydrous AuCl₃ begins to decompose to AuCl at around 160 °C; however at this will in turn undergo disproportionation at higher temperatures to give gold metal and AuCl₃. Liquids and solids (powders) are anhydrous if they are without water, i. ... jfkdjdfdfd--69. ...

AuCl₃ → AuCl + Cl₂ (>160 °C) General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ...

3 AuCl → AuCl₃ + 2 Au (>420 °C) General Name, Symbol, Number Gold, Au, 79 Chemical series transition metals Group, Period, Block 11 (IB), 6, d Density, Hardness 19300 kg/m3, 2. ...

AuCl₃ is a Lewis acid which readily forms complexes. For example with hydrochloric acid, chlorauric acid (HAuCl₄) is formed: In chemistry, a Lewis acid is any acid that can accept a pair of electrons and form a coordinate covalent bond, after the American chemist Gilbert Lewis. ... The chemical substance hydrochloric acid is the aqueous (water-based) solution of hydrogen chloride (HCl) gas. ...

HCl(aq) + AuCl₃(aq) → H⁺AuCl₄^&minus(aq) The chemical substance hydrochloric acid is the aqueous (water-based) solution of hydrogen chloride (HCl) gas. ... Drinking water This article focuses on water as we experience it every day. ...

Ionic chlorides such as KCl will also form the AuCl₄⁻ ion with AuCl₃. The chemical compound potassium chloride (KCl) is a metal halide composed of potassium and chlorine. ...

Aqueous solutions of AuCl₃ react with alkalis such as sodium hydroxide to form a precipitate of impure Au(OH)₃, which will dissolve in excess NaOH to form sodium aurate (NaAuO₂). If gently heated, Au(OH)₃ decomposes to gold(III) oxide (Au₂O₃) and then to gold metal. Sodium hydroxide (NaOH), also known as caustic soda or lye, is a caustic metallic base used in industry (mostly as a strong chemical base) in the manufacture of paper, textiles, and detergents. ...

Preparation

Gold(III) chloride is most often prepared by direct chlorination of the metal at high temperatures: Chlorination is the process of adding the element chlorine to water to make it fit for human consumption (potable) or to water intended for swimming or bathing in order to keep it from spreading disease. ...

2 Au + 3 Cl₂ → 2 AuCl₃ General Name, Symbol, Number Gold, Au, 79 Chemical series transition metals Group, Period, Block 11 (IB), 6, d Density, Hardness 19300 kg/m3, 2. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ...

Uses

Gold(III) chloride is one of the most common gold compounds and it is therefore used as the starting point for the synthesis of many other gold compounds, for example the water-soluble cyanide complex KAu(CN)₄: A cyanide is any chemical compound that contains the group C≡N, with the carbon atom triple bonded to the nitrogen atom. ... A complex in chemistry and biochemistry is a reversible association of molecules, atoms, or ions through weak non-covalent chemical bonds. ...

AuCl₃ + 4 KCN → KAu(CN)₄ + 3 KCl Potassium cyanide or KCN is the salt of potassium and hydrogen cyanide. ... The chemical compound potassium chloride (KCl) is a metal halide composed of potassium and chlorine. ...

Gold(III) salts, especially NaAuCl₄ (made from AuCl₃ + NaCl), provide a non-toxic alternative to mercury(II) salts as catalysts for alkyne reactions. One important reaction of this sort is the hydration of terminal alkynes to produce methyl ketones, for example^[7]: In chemistry, salt is a general term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. ... Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with formula NaCl. ... General Name, Symbol, Number Mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12 (IIB), 6, d Density, Hardness liquid 13,579 kg/m3 solid @ −39 °C 15,600 kg/m3 1. ... A catalyst (Greek: καταλύτης, catalytis) is a substance that accelerates the rate of a chemical reaction, at some temperature, but without itself being transformed or consumed by the reaction (see also catalysis). ... Alkynes are hydrocarbons that have at least one triple bond between carbon atoms. ... A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a compound that contains this functional group. ...

Image File history File links Hydration of an alkyne to give a 92% yield of a ketone in the presence of w:Gold(III) chloride. ...

Ketones are generally formed in over 90% yield under these conditions. Also useful is the related amination of alkynes which can use gold(III) catalysis. Amination is the process by which an amine group is introduced into an organic molecule. ...

In recent years AuCl₃ has begun to attract the interest of organic chemists as a mild acid catalyst for other reactions such as alkylation of aromatics and a conversion of furans to phenols (see below). Such reactions find use in organic synthesis and in the pharmaceutical industry. For example, 2-methylfuran (sylvan) undergoes smooth alkylation by methyl vinyl ketone at the 5-position: Alkylation is the transfer of an alkyl group from one molecule to another. ... An aromatic hydrocarbon (abbreviated as AH), or arene is a hydrocarbon, the molecular structure of which incorporates one or more planar sets of six carbon atoms that are connected by delocalised electrons numbering the same as if they consisted of alternating single and double covalent bonds. ... Furan, also known as furane and furfuran, is an aromatic heterocyclic organic compound, produced when wood, especially pine-wood, is distilled. ... Phenol, also known under the old name carbolic acid, is a colorless crystalline solid with a typical sweet tarry odor. ... Organic synthesis is the construction of organic molecules via chemical processes. ... Pharmacology (in Greek: pharmacon is drug, and logos is science) is the study of how chemical substances interfere with living systems. ...

Image File history File links Reaction of 2-methylfuran with methyl vinyl ketone in the presence of w:Gold(III) chloride, showing alkylation at the 5-position. ...

The reaction gives a 91% yield in only 40 minutes at room temperature, using only 1 mole% of AuCl₃ in acetonitrile. This yield is noteworthy since both the furan and the ketone are normally very sensitive to side-reactions such as polymerisation under acidic conditions. In some cases where alkynes are present, a phenol may be formed^[8]: Acetonitrile is an organic molecule, often used as a solvent, with the chemical formula of CH3CN. Also known as methyl cyanide, it is the simplest of the organic nitriles. ... Alkynes are hydrocarbons that have at least one triple bond between carbon atoms. ...

Image File history File links An unusual reaction between a furan and a tethered alkyne in the presence of w:gold(III) chloride, to form a new aromatic system as a phenol. ...

The reaction probably begins with a Diels-Alder reaction between the furan ring and the alkyne, followed by a complex rearrangement that leads to formation of the new aromatic ring. The Diels-Alder reaction is an organic chemical reaction (specifically, a cycloaddition) between a conjugated diene and a substituted alkene (commonly termed the dienophile) to form a substituted cyclohexene system. ...

Precautions

Gold(III) chloride should be handled wearing gloves and goggles, and direct contact with the material should be avoided.

Suppliers/Manufacturers

• Alfa
• Sigma-Aldrich
• Strem
• Fisher
• VWR

References

1. N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
2. Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
3. The Merck Index, 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960.
4. H. Nechamkin, The Chemistry of the Elements, McGraw-Hill, New York, 1968.
5. A. F. Wells, 'Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
6. 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.
7. Y. Fukuda, K. Utimoto, J. Org. Chem. 56, 3729-3731 (1991).
8. A. S. K. Hashmi, T. M. Frost, J. W. Bats, J. Am. Chem. Soc. 122, 11553-11554 (2000).