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About Gold

Gold Bohr

The notable properties of pure metallic gold are as follows: it is the most malleable and ductile of metals and an unusual color for elements of that class, is mostly non-reactive, conducts electricity well, and is extremely dense. The density of gold helped to drive its relative rarity, as gold present when the earth was formed would have largely sunk to the core of the planet. It is therefore believed that virtually all gold discovered by humans was deposited considerably later by meteorites containing the element. The low reactivity of gold explains why the metal was known to ancient societies despite its rarity: unlike most metals, it occurs mostly in its elemental form.

The rarity of gold, in combination with the ease with which it can be worked, its visual distinctiveness, and its resistance to chemical corrosion, made it an extremely unusual material and the object of much fascination. It was an obvious choice, then, for use as an ornamental status symbol and as a unit of monetary exchange. The oldest gold artifacts known have been dated to the 4th millennium BC, and the first gold coins (actually made of electrum, a natural gold-silver alloy) were minted around 600 BC in present-day Turkey. Gold remained a major component of monetary systems for much of the world into the twentieth century, as even when gold coinage became less common, most industrial economies used a gold standard to back their currencies. Gold standards started to be abandoned during World War I, and over time all modern industrialized nations switched to fiat currency systems.

Despite the fall of gold from an official monetary function, it is still widely viewed as valuable and used as an investment metal or means of storage of wealth, with many hoarding it as a hedge against inflation, and gold also remains a common metal used in fine jewelry. These functions still consume the majority of gold produced, despite a large number of other applications for the metal. Amalgams of gold and mercury have long been used in restorative dentistry for fillings and crowns, though concerns of mercury toxicity and the increasing availability of suitable composite materials as replacements have led to a decline in demand. Gold also finds many applications in electronics, where its high conductivity makes it attractive for wiring or as a coating for more easily corroded metals. Printed circuit boards often feature such thin protective gold layers. Thin films of gold are also useful for a variety of other functions. Gold can be manufactured to be thin enough to appear transparent, and thus be used in windows--in settings such as aircraft windshields--that can then be de-iced by passing electricity through the conductive film. Gold films are also excellent reflectors of electromagnetic radiation, including infrared light and radio waves, and are therefore used in infrared mirrors, heat shielding, and protective coatings on satellites and other equipment.

Despite being known for its low reactivity, it has long been known that gold can be dissolved in nitro-hydrochloric acid (aqua regia) and will form some compounds, including gold chlorides, gold oxides, and thiosulfates (such as gold sodium thiosulfate), and many applications of gold involve these less-familiar forms. Gold chloride solutions prepared by dissolving gold in aqua regia have been used to produce cranberry glass, the brilliant red color of which is now known to come from nanoscale gold particles dispersed within the glass.

Suspensions of such gold particles in liquid, also known as colloidal gold, are now of great interest due to their unique optical and electrical properties, in addition to their potential for useful interactions with biological systems. The electromagnetic absorption of colloidal gold solutions is tunable based on the size of the particles, a useful property with a side-effect of producing solutions that range in color from red to blue. Such solutions can be used in printable conductive inks for electronics, the production of sensors and photovoltaics, and the preparation of microscopy samples.

There is a significant history in modern biology of attaching tiny gold particles to a variety of biological probes, usually for use in electron microscopy, where the high electron-density of the gold particles makes them easy to visualize.Today, the ability to specifically target gold nanoparticles this way is being used in medicine, which prizes the ability to target specific tissues or cell types, including cancer cells. This allows them to be used in the detection of cancer cell locations and in the site-specific delivery of drugs and other therapeutic agents (including small RNA molecules under investigation for use as gene therapy). Additionally, gold nanorod structures absorb light in the near-infrared range, which easily passes through many human tissues. This fact has been exploited in cancer treatment: the heat generated when near-infrared light is absorbed by the rods kills the cells containing them, leaving surrounding cells largely unscathed.

Gold occurs most often as a native metal on its own or as natural gold-silver alloy. Most gold is mined in this form from either lode or placer deposits, and a small amount is produced as a byproduct of the processing of base metals. Additionally, gold is also frequently recycled from scrap, and many financial institutions still hold significant gold stockpiles.


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Gold is used in coinage and is a standard for most modern monetary systems. It is also used extensively for jewelry, dental restorations, and plating. It is used for coating certain space satellites, as it is inert and a good infrared reflector. The use of gold in electronics has seen significant growth, particularly within telecommunications, information technology and safety critical applications. Similarly, within computers there are usually gold-plated edge connectors. Gold bonding wires are used extensively within semiconductor packages and gold thick film inks are applied in the fabrication of hybrid circuits. High Purity (99.999%) Gold Oxide (Au2O3) Powder Gold's excellent solder wetting properties are used to form a very thin protective layer on copper laminate printed circuit boards. Gold is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%) Gold (Au) Sputtering TargetElemental or metallic forms include pellets, rod, powder and granules for evaporation source material purposes. Gold nanoparticles and nanopowders are also available. Gold oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Gold is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

American Elements assists our Gold customers with fulfilling the due diligence reporting requirements of the Conflict Mineral Provision (Section 1502) of the Dodd-Frank Act.

Gold Properties

Gold (Au) atomic and molecular weight, atomic number and elemental symbol Gold is a Block D, Group 11, Period 6 element. The number of electrons in each of Gold's shells is 2, 8, 18, 32, 18, 1 and its electronic configuration is [Xe] 4f142 5d10 6s1. The gold atom has a radius of and its Van der Waals radius is Gold Bohr ModelIn its elemental form, CAS 7440-57-5, gold has a metallic yellow appearance. Gold is a soft metal and is usually alloyed to give it more strength.Elemental Gold It is a good conductor of heat and electricity, and is unaffected by air and most reagents. It is one of the least reactive chemical elements. Gold is often found as a free element and with silver as a gold silver alloy. Less commonly, it is found in minerals as gold compounds, usually with tellurium. Gold was first discovered by early man c.a. 6000 BCE or earlier.

Symbol: Au
Atomic Number: 79
Atomic Weight: 196.9666
Element Category: transition metal
Group, Period, Block: 11, 6, d
Color: golden yellow
Other Names: Or, Oro, Ouro, Guld
Melting Point: 1064.18 °C,1947.52 °F, 1337.33 K
Boiling Point: 2856 °C,5173 °F, 3129 K
Density: 19.30 g/cm3
Liquid Density @ Melting Point: 17.31 g/cm3
Density @ 20°C: 19.32 g/cm3
Density of Solid: 19300 kg·m3
Specific Heat: 0.13 (kJ/kg K)
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: 7250 K,  510.0 Mpa
Heat of Fusion (kJ·mol-1): 12.7
Heat of Vaporization (kJ·mol-1): 343.1
Heat of Atomization (kJ·mol-1): 365.93
Thermal Conductivity: 318 W·m-1·K-1
Thermal Expansion: (25 °C) 14.2 µm·m-1·K-1
Electrical Resistivity: (20 °C) 22.14 nΩ·m
Tensile Strength: 120 MPa
Molar Heat Capacity: 25.418 J·mol-1·K-1
Young's Modulus: 79 GPa
Shear Modulus: 27 GPa
Bulk Modulus: 180 GPa
Poisson Ratio: 0.44
Mohs Hardness: 2.5
Vickers Hardness: 216 MPa
Brinell Hardness: 25 HB
Speed of Sound: (r.t.) 2030 m·s-1
Pauling Electronegativity: 2.54
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.42
Mulliken-Jaffe Electronegativity: 1.87 (s orbital)
Allen Electronegativity: N/A
Pauling Electropositivity: 1.46
Reflectivity (%): 95
Refractive Index: N/A
Electrons: 79
Protons: 79
Neutrons: 118
Electron Configuration: [Xe] 4f142 5d10 6s1
Atomic Radius: 144 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 136±6 pm
Covalent Radius (Å): 1.3
Van der Waals Radius: 217 pm
Oxidation States: 5, 4, 3, 2, 1, -1, -2 (amphoteric oxide)
Phase: Solid
Crystal Structure: lattice face centered cubic
Magnetic Ordering: diamagnetic
Electron Affinity (kJ·mol-1) 222.785
1st Ionization Energy: 890.13 kJ·mol-1
2nd Ionization Energy: 1977.96 kJ·mol-1
3rd Ionization Energy: N/A
CAS Number: 7440-57-5
EC Number: 231-165-9
MDL Number: MFCD00003436
Beilstein Number: N/A
SMILES Identifier: [Au]
InChI Identifier: InChI=1S/Au
PubChem CID: 23985
ChemSpider ID: 22421
Earth - Total: 257 ppb
Mercury - Total:  516 ppm
Venus - Total: 250 ppb
Earth - Seawater (Oceans), ppb by weight: 0.05
Earth - Seawater (Oceans), ppb by atoms: 0.0016
Earth -  Crust (Crustal Rocks), ppb by weight: 3.1
Earth -  Crust (Crustal Rocks), ppb by atoms: 0.3
Sun - Total, ppb by weight: 1
Sun - Total, ppb by atoms: 0.01
Stream, ppb by weight: 0.002
Stream, ppb by atoms: 0.00001
Meterorite (Carbonaceous), ppb by weight: 170
Meterorite (Carbonaceous), ppb by atoms: 20
Typical Human Body, ppb by weight: 100
Typical Human Body, ppb by atom: 3
Universe, ppb by weight: 0.6
Universe, ppb by atom: 0.004
Discovered By: N/A
Discovery Date: Prior to 6000 BC
First Isolation: N/A

Health, Safety & Transportation Information for Gold

Gold is not toxic in its elemental form; however, safety data for gold and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab.

Safety Data
Signal Word N/A
Hazard Statements N/A
Hazard Codes N/A
Risk Codes N/A
Safety Precautions N/A
RTECS Number N/A
Transport Information N/A
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)
Review and Print SDS for Gold Metal


Date Created: 05/15/2015
Date Revised: 05/15/2015


Product Name: Gold Metal

Product Number: All applicable American Elements product codes, e.g. AU-M-02, AU-M-03, AU-M-04, AU-M-05

CAS #: 7440-57-5

Relevant identified uses of the substance: Scientific research and development

Supplier details:
American Elements
1093 Broxton Ave. Suite 2000
Los Angeles, CA 90024
Tel: +1 310-208-0551
Fax: +1 310-208-0351

Emergency telephone number:
Domestic, North America +1 800-424-9300
International +1 703-527-3887


Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008
The substance is not classified as hazardous to health or the environment according to the CLP regulation.
Classification according to Directive 67/548/EEC or Directive 1999/45/EC
Not applicable
Information concerning particular hazards for human and environment:
No information known.
Hazards not otherwise classified
No information known.
Label elements
Labelling according to Regulation (EC) No 1272/2008
Not applicable
Hazard pictograms
Not applicable
Signal word
Not applicable
Hazard statements
Not applicable
WHMIS classification
Not controlled
Classification system
HMIS ratings (scale 0-4)
(Hazardous Materials Identification System)

Health (acute effects) = 0
Flammability = 0
Physical Hazard = 0
Other hazards
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable


Chemical characterization: Substances
CAS# Description:
7440-57-5 Gold
Identification number(s):
EC number: 231-165-9


Description of first aid measures
After inhalation
Supply fresh air. If required, provide artificial respiration. Keep patient warm.
Seek immediate medical advice.
After skin contact
Immediately wash with water and soap and rinse thoroughly.
Seek immediate medical advice.
After eye contact
Rinse opened eye for several minutes under running water. Then consult a doctor.
After swallowing
Seek medical treatment.
Information for doctor
Most important symptoms and effects, both acute and delayed
No further relevant information available.
Indication of any immediate medical attention and special treatment needed
No further relevant information available


Extinguishing media
Suitable extinguishing agents
Product is not flammable. Use fire-fighting measures that suit the surrounding fire.
Special hazards arising from the substance or mixture
If this product is involved in a fire, the following can be released:
Metal oxide fume
Advice for firefighters
Protective equipment:
Wear self-contained respirator.
Wear fully protective impervious suit.


Personal precautions, protective equipment and emergency procedures
Wear protective equipment. Keep unprotected persons away
Ensure adequate ventilation
Environmental precautions:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow product to reach sewage system or any water course.
Do not allow to penetrate the ground/soil.
Methods and material for containment and cleaning up:
Pick up mechanically.
Prevention of secondary hazards:
No special measures required.
Reference to other sections
See Section 7 for information on safe handling
See Section 8 for information on personal protection equipment.
See Section 13 for disposal information


Precautions for safe handling
Keep container tightly sealed.
Store in cool, dry place in tightly closed containers.
Information about protection against explosions and fires:
The product is not flammable
Conditions for safe storage, including any incompatibilities
Requirements to be met by storerooms and receptacles:
No special requirements.
Information about storage in one common storage facility:
Do not store together with oxidizing and acidic materials.
Further information about storage conditions:
Keep container tightly sealed.
Store in cool, dry conditions in well sealed containers.
Specific end use(s)
No further relevant information available.


Additional information about design of technical systems:
Properly operating chemical fume hood designed for hazardous chemicals and having an average face velocity of at least 100 feet per minute.
Control parameters
Components with limit values that require monitoring at the workplace:
The product does not contain any relevant quantities of materials with critical values that have to be monitored at the workplace.
Additional information: No data
Exposure controls
Personal protective equipment
General protective and hygienic measures
The usual precautionary measures for handling chemicals should be followed.
Keep away from foodstuffs, beverages and feed.
Remove all soiled and contaminated clothing immediately.
Wash hands before breaks and at the end of work.
Maintain an ergonomically appropriate working environment.
Breathing equipment:
Use suitable respirator when high concentrations are present.
Protection of hands:
Impervious gloves
Check protective gloves prior to each use for their proper condition.
The selection of suitable gloves not only depends on the material, but also on quality. Quality will vary from manufacturer to manufacturer.
Penetration time of glove material (in minutes)
Not determined
Eye protection: Safety glasses
Body protection: Protective work clothing.


Information on basic physical and chemical properties
General Information
Form: Solid in various form
Color: Gold colored
Odor: Not determined
Odor threshold: Not determined.
pH-value: Not applicable.
Change in condition
Melting point/Melting range: 1064 °C (1947 °F)
Boiling point/Boiling range: 2808 °C (5086 °F)
Sublimation temperature / start: Not determined
Flammability (solid, gaseous): Not determined.
Ignition temperature: Not determined
Decomposition temperature: Not determined
Auto igniting: Not determined.
Danger of explosion: Product does not present an explosion hazard.
Explosion limits:
Lower: Not determined
Upper: Not determined
Vapor pressure: Not applicable.
Density at 20 °C (68 °F): 19.32 g/cm³ (161.225 lbs/gal)
Relative density: Not determined.
Vapor density: Not applicable.
Evaporation rate: Not applicable.
Solubility in / Miscibility with Water: Insoluble
Partition coefficient (n-octanol/water): Not determined.
dynamic: Not applicable.
kinematic: Not applicable.
Other information
No further relevant information available


No information known.
Chemical stability
Stable under recommended storage conditions.
Thermal decomposition / conditions to be avoided:
Decomposition will not occur if used and stored according to specifications.
Possibility of hazardous reactions
No dangerous reactions known
Conditions to avoid
No further relevant information available.
Incompatible materials:
Oxidizing agents
Hazardous decomposition products:
Metal oxide fume


Information on toxicological effects
Acute toxicity:
The Registry of Toxic Effects of Chemical Substances (RTECS) contains acute toxicity data for this substance.
LD/LC50 values that are relevant for classification: No data
Skin irritation or corrosion: May cause irritation
Eye irritation or corrosion: May cause irritation
Sensitization: No sensitizing effects known.
Germ cell mutagenicity:
The Registry of Toxic Effects of Chemical Substances (RTECS) contains mutation data for this substance.
No classification data on carcinogenic properties of this material is available from the EPA, IARC, NTP, OSHA or ACGIH.
The Registry of Toxic Effects of Chemical Substances (RTECS) contains tumorigenic and/or carcinogenic and/or neoplastic data for this substance.
Reproductive toxicity: No effects known.
Specific target organ system toxicity - repeated exposure: No effects known.
Specific target organ system toxicity - single exposure: No effects known.
Aspiration hazard: No effects known.
Subacute to chronic toxicity: No effects known.
Additional toxicological information:
To the best of our knowledge the acute and chronic toxicity of this substance is not fully known.


Aquatic toxicity:
No further relevant information available.
Persistence and degradability
No further relevant information available.
Bioaccumulative potential
No further relevant information available.
Mobility in soil
No further relevant information available.
Additional ecological information:
General notes:
Do not allow material to be released to the environment without proper governmental permits.
Avoid transfer into the environment.
Results of PBT and vPvB assessment
PBT: Not applicable.
vPvB: Not applicable.
Other adverse effects
No further relevant information available


Waste treatment methods
Consult state, local or national regulations to ensure proper disposal.
Uncleaned packagings:
Disposal must be made according to official regulations.


Not applicable
UN proper shipping name
Not applicable
Transport hazard class(es)
Not applicable
Packing group
Not applicable
Environmental hazards:
Not applicable.
Special precautions for user
Not applicable.
Transport in bulk according to Annex II of MARPOL73/78 and the IBC Code
Not applicable.
Transport/Additional information:
Marine Pollutant (DOT):
UN "Model Regulation":


Safety, health and environmental regulations/legislation specific for the substance or mixture
National regulations
All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory.
All components of this product are listed on the Canadian Domestic Substances List (DSL).
SARA Section 313 (specific toxic chemical listings)
Substance is not listed.
California Proposition 65
Prop 65 - Chemicals known to cause cancer
Substance is not listed.
Prop 65 - Developmental toxicity
Substance is not listed.
Prop 65 - Developmental toxicity, female
Substance is not listed.
Prop 65 - Developmental toxicity, male
Substance is not listed.
Information about limitation of use:
For use only by technically qualified individuals.
Other regulations, limitations and prohibitive regulations
Substance of Very High Concern (SVHC) according to the REACH Regulations (EC) No. 1907/2006.
Substance is not listed.
The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed.
Substance is not listed.
Annex XIV of the REACH Regulations (requiring Authorisation for use)
Substance is not listed.
REACH - Pre-registered substances
Substance is listed.
Chemical safety assessment:
A Chemical Safety Assessment has not been carried out.


Safety Data Sheet according to Regulation (EC) No. 1907/2006 (REACH). The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. American Elements shall not be held liable for any damage resulting from handling or from contact with the above product. See reverse side of invoice or packing slip for additional terms and conditions of sale. COPYRIGHT 1997-2016 AMERICAN ELEMENTS. LICENSED GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.

Gold Isotopes

Gold (Au) has one stable isotope, 197Au

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
169Au 168.99808(32)# 150# µs Unknown 1/2+# N/A 1285.98 -
170Au 169.99612(22)# 310(50) µs [286(+50-40) µs] Unknown (2-) N/A 1294.05 -
171Au 170.991879(28) 17 µs p to 170Pt; a to 167Ir (1/2+) N/A 1302.13 -
172Au 171.99004(17)# 6.3 ms a to 168Ir; p to 171Pt high N/A 1310.21 -
173Au 172.986237(28) 20 ms a to 169Ir; ß- to 173Pt (1/2+) N/A 1327.61 -
174Au 173.98476(11)# 120 ms a to 170Ir; ß- to 174Pt low N/A 1335.68 -
175Au 174.98127(5) 185 ms a to 171Ir; ß- to 175Pt 1/2+# N/A 1343.76 -
176Au 175.98010(11)# 1.08(17) s [0.84(+17-14) s] a to 172Ir; ß- to 176Pt (5-) N/A 1351.84 -
177Au 176.976865(14) 1.462(32) s ß- to 177Pt; a to 173Ir (1/2+,3/2+) N/A 1369.24 -
178Au 177.97603(6) 2.6(5) s ß- to 178Pt; a to 174Ir N/A N/A 1377.32 -
179Au 178.973213(18) 3.3 s ß- to 179Pt; a to 175Ir 5/2-# N/A 1385.39 -
180Au 179.972521(23) 8.1(3) s ß- to 180Pt; a to 176Ir N/A N/A 1393.47 -
181Au 180.970079(21) 13.7(14) s ß- to 181Pt; a to 177Ir (3/2-) N/A 1401.55 -
182Au 181.969618(22) 15.5(5) s ß- to 182Pt; a to 178Ir (2+) N/A 1418.95 -
183Au 182.967593(11) 42.8(10) s ß- to 183Pt; a to 179Ir (5/2)- N/A 1427.03 -
184Au 183.967452(24) 20.6(9) s ß- to 184Pt 5+ N/A 1435.1 -
185Au 184.965789(28) 4.25(6) min ß- to 185Pt; a to 180Ir 5/2- N/A 1443.18 -
186Au 185.965953(23) 10.7(5) min ß- to 186Pt; a to 181Ir 3- N/A 1451.26 -
187Au 186.964568(27) 8.4(3) min ß- to 187Pt; a to 182Ir 1/2+ N/A 1459.34 -
188Au 187.965324(22) 8.84(6) min ß- to 188Pt 1(-) N/A 1467.42 -
189Au 188.963948(22) 28.7(3) min ß- to 189Pt; a to 184Ir 1/2+ N/A 1475.5 -
190Au 189.964700(17) 42.8(10) min ß- to 190Pt; a to 185Ir 1- N/A 1483.58 -
191Au 190.96370(4) 3.18(8) h ß- to 191Pt 3/2+ N/A 1491.66 -
192Au 191.964813(17) 4.94(9) h ß- to 192Pt 1- N/A 1499.73 -
193Au 192.964150(11) 17.65(15) h ß- to 193Pt; a to 188Ir 3/2+ N/A 1507.81 -
194Au 193.965365(11) 38.02(10) h EC to 194Pt 1- 0.075 1515.89 -
195Au 194.9650346(14) 186.098(47) d EC to 195Pt 3/2+ 0.149 1523.97 -
196Au 195.966570(3) 6.1669(6) d EC to 196Pt; ß- to 196Hg 2- 0.591 1532.05 -
197Au 196.9665687(6) Observationally Stable - 3/2+ 0.148159 1540.13 100
198Au 197.9682423(6) 2.69517(21) d ß- to 198Hg 2- 0.5934 1548.21 -
199Au 198.9687652(6) 3.139(7) d ß- to 199Hg 3/2+ 0.2715 1556.28 -
200Au 199.97073(5) 48.4(3) min ß- to 200Hg 1(-) N/A 1555.05 -
201Au 200.971657(3) 26(1) min ß- to 201Hg 3/2+ N/A 1563.13 -
202Au 201.97381(18) 28.8(19) s ß- to 202Hg (1-) N/A 1571.2 -
203Au 202.975155(3) 53(2) s ß- to 203Hg 3/2+ N/A 1579.28 -
204Au 203.97772(22)# 39.8(9) s ß- to 204Hg (2-) N/A 1587.36 -
205Au 204.97987(32)# 31(2) s ß- to 205Hg 3/2+ N/A 1595.44 -