Gold (Au)
Introduction
Gold is a chemical element with an atomic number of 79 in the periodic table of elements. It’s a precious metal found in its free elemental form in the beds of streams, alluvial deposits, and rock veins. Being a member of the transition metals family of periodic table elements, gold has one valence electron that supports the formation of univalence compounds with this chemical element.
Fact Box
Chemical and Physical Properties of Gold
The symbol in the periodic table of elements: Au
Atomic number: 79
Atomic weight (mass): 196.967 g.mol -1
Group number: 11
Period: 6
Color: yellow with a reddish hue
Physical state: Solid and soft metal
Half-life: N/A
Electronegativity according to Pauling: 2.54
Density: 19.3
Melting point: 1064.18°C, 1947.52°F, 1337.33K
Boiling point: 2836°C, 5137°F, 3109 K
Van der Waals radius: 166 pm
Ionic radius: .85 (+3) Å
Isotopes: 169-206Au
Most characteristic isotope: 197Au
Electronic shell: [Xe] 4f145d106s1
The energy of the first ionization: 9.2257 eV
The energy of the second ionization: X+ → X2+ + e−
The energy of the third ionization: X2+ → X3+ + e−
Discovery date: In 1848 by James W. Marshall
With the periodic table symbol Au, atomic number 79, the atomic mass of 196.967 g.mol -1, and electronic configuration [Xe] 4f145d106s1, gold is a ductile metal that reaches its boiling point at 2836°C, 5137°F, 3109 K, while the melting point is achieved at 1064.18°C, 1947.52°F, 1337.33 K. This soft and malleable member of the transition metals family of elements in the periodic table has an electronegativity of 2.54 according to Pauling, whereas the atomic radius according to van der Waals is 166 pm.
Despite being resistant to most of the acids, gold can dissolve in nitric acid and hydrochloric acid mixture labeled as aqua regia. The nitric acid contained in this chemical mixture can dissolve silver by itself, but this is not the case with gold. Due to this property, gold can be refined and detected in metal-made objects using the nitric acid test.
How Was Gold Discovered?
The ancient civilizations were familiar with gold. It’s the earliest metal used by the Egyptians, who considered this chemical substance as a symbol of affluence and beauty.
The modern-day story of how gold was discovered includes a truly fortunate stroke of serendipity. It happened in 1848, in California, United States when one James W. Marshall was building a sawmill for John A. Sutter, the sun was merciless. The scorching hot rays made James Marshal pause a bit from the work. As he tried to sweep away the drops of sweat from his forehead, he noticed a shiny nugget on the ground reflecting the sunlight. It was a gold nugget.
This discovery triggered the “Gold rush”. After hearing the information on the serendipitous discovery, more than 300,000 people hurried to Sutter’s Mill in Coloma, California. They were all driven to travel a long way and search for gold led by the dream of becoming rich overnight.
How Did Gold Get Its Name?
The Latin ‘aurum’ is the word that inspired the symbol for gold in the periodic table of elements (Au), but what gave gold its name is the specific color of this precious metal. Namely, ‘geolo’ is the Anglo-Saxon word for ‘yellow’.
Where Can You Find Gold?
While larger nuggets or grains can be found in their elemental form in rock veins and river stream beds, the universe has its share of gold production. When the neutron stars collide and cause supernova explosions, the dust produced contains traces of gold produced by rapid neutron capture.
Gold Price FAQ
What Is the Use of Gold in Coinage and Monetary Systems?
Since ancient times, gold has been considered a symbol of wealth, a ‘safe haven’ asset, and a good investment. The Kingdom of Lydia (today’s modern Turkey) was the place where the first gold coins were mint around 640 BC. They were made from an alloy of gold and silver, known as electrum.
Today, even after so much time has passed, this precious metal still represents a great economic force. Namely, when the times are bad for the economy, merchants tend to invest or trade in gold since the price of gold goes up at such times. This was especially apparent after the coronavirus pandemic outbreak in February-March 2020, both in the United States and worldwide. The expectations for new waves of COVID-19 raised the fear that it will cause a new downfall of the US dollar.
In order to determine the potential value of gold as an investment, merchants and traders use two models:
- Gold futures prices,
- Gold spot price.
With the first model, traders try to estimate the demand and supplies of gold, as well as transport and storage costs. Based upon these estimations, they form the price of gold which can increase over time, especially if it is in market demand. The second model used for determining the potential value of gold refers to the price of gold at the time of purchase. The gold spot price changes even more rapidly than gold future prices. Also, the spot price of gold is typically higher than the first offer on the stock market.
The conditions on the gold market, the available supplies of this precious metal, currency depreciation, i.e. the loss of currency value of the country trading with gold, etc are among the factors that influence the formation of gold prices. The most significant international gold markets are the America Gold Market, London Gold Market, Zurich Gold Market, and the Hong Kong Gold Market.
At the international gold markets, gold is traded in US dollars, while the current price of gold calculated per troy ounce is reported in real-time as a live spot gold price in Euro, Yen, AUD, CAD, GBP, and CHF during the course of the 24-hour trading on international gold markets. The live gold prices with an XAU/USD price chart are derived every 10 seconds and can be followed on both iPhone devices or Android widgets. The live Nasdaq futures prices on this market are also available via Google searches of the Internet.
What Is a Gold Standard?
A gold standard is a monetary system in which the currency value is directly dependent on the gold value at a given moment. In this way, money can be converted into gold in the central banks of the countries that have implemented the gold standard in their monetary systems. However, this system has been rejected in the 1930s and substituted with fiat money, the currency of a country used as a means of payment. After World War II, convertible currencies with fixed exchange rates replaced the gold standard in order to maintain a more stable economy of the countries.
What Are Gold Bullions?
Just like with the other precious metals (silver, platinum, and palladium), these gold bars or bullion coins hold the value as physical gold even in uncertain economic times. When the economy faces a downfall, the gold prices typically soar to a record high. The bullions made of precious metal can lose some of the value if the gold and silver price drops on the market. The U.S. Federal Reserve Bank in New York is the largest gold depository in the world, while the New York Mercantile Exchange (COMEX), the London Bullion Market, the Euronext/LIFFE, the Chicago Board of Trade, the Tokyo Commodity Exchange are the most influential stock exchanges.
What Are Gold Futures?
Gold futures refer to the agreement on the weight of gold and its spot price between the buyer and the seller in order to sell gold on the stock exchange. The agreement determines the gold price per gram, per ounce, and per 1 kilo of the precious metal. This enables trading with commodities without a need to refund the entire amount.
What Is Bitcoin?
Bitcoin gold is a digital cryptocurrency used with the electronic payment system that is not under the control of any government in the world.
What Is an Exchange-Traded Fund (ETF)?
ETF, or an Exchange-traded fund refers to securities (gold bullions, bitcoins, gold coins, stocks) that are traded on the stock exchanges. A gold certificate is a document issued by a central bank that declares the ownership of a gold quantity that is stored in the bank.
How Dangerous Is Gold?
Gold is a non-toxic substance. It’s used in dentistry as a gold filling which is proven not to have any harmful effects upon human health. However, when it comes to contact with the skin, it may cause allergy, rashes, and itching.
Isotopes of Gold
Gold-197 (197Au) is the only stable and naturally occurring isotope of this chemical substance with an infinite half-life. In this regard, gold is considered as both a mononuclidic and monoisotopic chemical element of the periodic table.
This chemical substance has 36 unstable radioisotopes, some of which have a half-life of less than a minute. The half-life of 186 days makes the radioisotope gold-195 (195Au) the most stable in its group.
The following is a tabular representation of gold’s isotopes, their half-life, and decay mode:
| Nuclide
[n 1] |
Z | N | Isotopic mass (Da)
[n 2][n 3] |
Half-life
[n 4] |
Decay
mode [n 5] |
Daughter
isotope [n 6][n 7] |
Spin and
parity [n 8][n 4] |
Natural abundance (mole fraction) | |
| Excitation energy[n 4] | Normal proportion | Range of variation | |||||||
| 169Au | 79 | 90 | 168.99808(32)# | 150# μs | 1/2+# | ||||
| 170Au | 79 | 91 | 169.99612(22)# | 310(50) μs
[286(+50−40) μs] |
(2−) | ||||
| 170mAu | 275(14) keV | 630(60) μs
[0.62(+6−5) ms] |
(9+) | ||||||
| 171Au | 79 | 92 | 170.991879(28) | 30(5) μs | p | 170Pt | (1/2+) | ||
| α (rare) | 167Ir | ||||||||
| 171mAu | 250(16) keV | 1.014(19) ms | α (54%) | 167Ir | 11/2− | ||||
| p (46%) | 170Pt | ||||||||
| 172Au | 79 | 93 | 171.99004(17)# | 4.7(11) ms | α (98%) | 168Ir | high | ||
| p (2%) | 171Pt | ||||||||
| 173Au | 79 | 94 | 172.986237(28) | 25(1) ms | α | 169Ir | (1/2+) | ||
| β+ (rare) | 173Pt | ||||||||
| 173mAu | 214(23) keV | 14.0(9) ms | α (96%) | 169Ir | (11/2−) | ||||
| β+ (4%) | 173Pt | ||||||||
| 174Au | 79 | 95 | 173.98476(11)# | 139(3) ms | α | 170Ir | low | ||
| β+ (rare) | 174Pt | ||||||||
| 174mAu | 360(70)# keV | 171(29) ms | high | ||||||
| 175Au | 79 | 96 | 174.98127(5) | 100# ms | α (82%) | 171Ir | 1/2+# | ||
| β+ (18%) | 175Pt | ||||||||
| 175mAu | 200(30)# keV | 156(3) ms | α | 171Ir | 11/2−# | ||||
| β+ | 175Pt | ||||||||
| 176Au | 79 | 97 | 175.98010(11)# | 1.08(17) s
[0.84(+17−14) s] |
α (60%) | 172Ir | (5−) | ||
| β+ (40%) | 176Pt | ||||||||
| 176mAu | 150(100)# keV | 860(160) ms | (7+) | ||||||
| 177Au | 79 | 98 | 176.976865(14) | 1.462(32) s | β+ (60%) | 177Pt | (1/2+, 3/2+) | ||
| α (40%) | 173Ir | ||||||||
| 177mAu | 216(26) keV | 1.180(12) s | 11/2− | ||||||
| 178Au | 79 | 99 | 177.97603(6) | 2.6(5) s | β+ (60%) | 178Pt | |||
| α (40%) | 174Ir | ||||||||
| 179Au | 79 | 100 | 178.973213(18) | 7.1(3) s | β+ (78%) | 179Pt | 5/2−# | ||
| α (22%) | 175Ir | ||||||||
| 179mAu | 99(16) keV | (11/2−) | |||||||
| 180Au | 79 | 101 | 179.972521(23) | 8.1(3) s | β+ (98.2%) | 180Pt | |||
| α (1.8%) | 176Ir | ||||||||
| 181Au | 79 | 102 | 180.970079(21) | 13.7(14) s | β+ (97.3%) | 181Pt | (3/2−) | ||
| α (2.7%) | 177Ir | ||||||||
| 182Au | 79 | 103 | 181.969618(22) | 15.5(4) s | β+ (99.87%) | 182Pt | (2+) | ||
| α (.13%) | 178Ir | ||||||||
| 183Au | 79 | 104 | 182.967593(11) | 42.8(10) s | β+ (99.2%) | 183Pt | (5/2)− | ||
| α (.8%) | 179Ir | ||||||||
| 183m1Au | 73.3(4) keV | >1 μs | (1/2)+ | ||||||
| 183m2Au | 230.6(6) keV | <1 μs | (11/2)− | ||||||
| 184Au | 79 | 105 | 183.967452(24) | 20.6(9) s | β+ | 184Pt | 5+ | ||
| 184mAu | 68.46(1) keV | 47.6(14) s | β+ (70%) | 184Pt | 2+ | ||||
| IT (30%) | 184Au | ||||||||
| α (.013%) | 180Ir | ||||||||
| 185Au | 79 | 106 | 184.965789(28) | 4.25(6) min | β+ (99.74%) | 185Pt | 5/2− | ||
| α (.26%) | 181Ir | ||||||||
| 185mAu | 100(100)# keV | 6.8(3) min | 1/2+# | ||||||
| 186Au | 79 | 107 | 185.965953(23) | 10.7(5) min | β+ (99.9992%) | 186Pt | 3− | ||
| α (8×10−4%) | 182Ir | ||||||||
| 186mAu | 227.77(7) keV | 110(10) ns | 2+ | ||||||
| 187Au | 79 | 108 | 186.964568(27) | 8.4(3) min | β+ (99.997%) | 187Pt | 1/2+ | ||
| α (.003%) | 183Ir | ||||||||
| 187mAu | 120.51(16) keV | 2.3(1) s | IT | 187Au | 9/2− | ||||
| 188Au | 79 | 109 | 187.965324(22) | 8.84(6) min | β+ | 188Pt | 1(−) | ||
| 189Au | 79 | 110 | 188.963948(22) | 28.7(3) min | β+ (99.9997%) | 189Pt | 1/2+ | ||
| α (3×10−4%) | 185Ir | ||||||||
| 189m1Au | 247.23(16) keV | 4.59(11) min | β+ | 189Pt | 11/2− | ||||
| IT (rare) | 189Au | ||||||||
| 189m2Au | 325.11(16) keV | 190(15) ns | 9/2− | ||||||
| 189m3Au | 2554.7(12) keV | 242(10) ns | 31/2+ | ||||||
| 190Au | 79 | 111 | 189.964700(17) | 42.8(10) min | β+ | 190Pt | 1− | ||
| α (10−6%) | 186Ir | ||||||||
| 190mAu | 200(150)# keV | 125(20) ms | IT | 190Au | 11−# | ||||
| β+ (rare) | 190Pt | ||||||||
| 191Au | 79 | 112 | 190.96370(4) | 3.18(8) h | β+ | 191Pt | 3/2+ | ||
| 191m1Au | 266.2(5) keV | 920(110) ms | IT | 191Au | (11/2−) | ||||
| 191m2Au | 2490(1) keV | >400 ns | |||||||
| 192Au | 79 | 113 | 191.964813(17) | 4.94(9) h | β+ | 192Pt | 1− | ||
| 192m1Au | 135.41(25) keV | 29 ms | IT | 192Au | (5#)+ | ||||
| 192m2Au | 431.6(5) keV | 160(20) ms | (11−) | ||||||
| 193Au | 79 | 114 | 192.964150(11) | 17.65(15) h | β+ (100%) | 193Pt | 3/2+ | ||
| α (10−5%) | 189Ir | ||||||||
| 193m1Au | 290.19(3) keV | 3.9(3) s | IT (99.97%) | 193Au | 11/2− | ||||
| β+ (.03%) | 193Pt | ||||||||
| 193m2Au | 2486.5(6) keV | 150(50) ns | (31/2+) | ||||||
| 194Au | 79 | 115 | 193.965365(11) | 38.02(10) h | β+ | 194Pt | 1− | ||
| 194m1Au | 107.4(5) keV | 600(8) ms | IT | 194Au | (5+) | ||||
| 194m2Au | 475.8(6) keV | 420(10) ms | (11−) | ||||||
| 195Au | 79 | 116 | 194.9650346(14) | 186.098(47) d | EC | 195Pt | 3/2+ | ||
| 195mAu | 318.58(4) keV | 30.5(2) s | IT | 195Au | 11/2− | ||||
| 196Au | 79 | 117 | 195.966570(3) | 6.1669(6) d | β+ (93.05%) | 196Pt | 2− | ||
| β− (6.95%) | 196Hg | ||||||||
| 196m1Au | 84.660(20) keV | 8.1(2) s | IT | 196Au | 5+ | ||||
| 196m2Au | 595.66(4) keV | 9.6(1) h | 12− | ||||||
| 197Au[n 9] | 79 | 118 | 196.9665687(6) | Stable | 3/2+ | 1.0000 | |||
| 197mAu | 409.15(8) keV | 7.73(6) s | IT | 197Au | 11/2− | ||||
| 198Au | 79 | 119 | 197.9682423(6) | 2.69517(21) d | β− | 198Hg | 2− | ||
| 198m1Au | 312.2200(20) keV | 124(4) ns | 5+ | ||||||
| 198m2Au | 811.7(15) keV | 2.27(2) d | IT | 198Au | (12−) | ||||
| 199Au | 79 | 120 | 198.9687652(6) | 3.139(7) d | β− | 199Hg | 3/2+ | ||
| 199mAu | 548.9368(21) keV | 440(30) μs | (11/2)− | ||||||
| 200Au | 79 | 121 | 199.97073(5) | 48.4(3) min | β− | 200Hg | 1(−) | ||
| 200mAu | 970(70) keV | 18.7(5) h | β− (82%) | 200Hg | 12− | ||||
| IT (18%) | 200Au | ||||||||
| 201Au | 79 | 122 | 200.971657(3) | 26(1) min | β− | 201Hg | 3/2+ | ||
| 201m1Au | 594(5) keV | 730(630) μs | (11/2-) | ||||||
| 201m2Au | 1610(5) keV | 5.6(2.4) μs | (11/2-) | ||||||
| 202Au | 79 | 123 | 201.97381(18) | 28.8(19) s | β− | 202Hg | (1−) | ||
| 203Au | 79 | 124 | 202.975155(3) | 60(6) s | β− | 203Hg | 3/2+ | ||
| 203mAu | 641(3) keV | 140(44) μs | IT | 203Au | 11/2−# | ||||
| 204Au | 79 | 125 | 203.97772(22)# | 38.3(1.3) s | β− | 204Hg | (2−) | ||
| 204mAu | 3816(1000)# keV | 2.1(0.3) μs | IT | 204Au | 16+# | ||||
| 205Au | 79 | 126 | 204.97985(21)# | 32.5(1.4) s | β− | 205Hg | 3/2+# | ||
| 205m1Au | 907(5) keV | 6(2) s | 11/2−# | ||||||
| 205m2Au | 2850(5) keV | 163(5) ns | 19/2+# | ||||||
| 206Au | 79 | 127 | 205.98474(32)# | 47(11) s | β− | 206Hg | (5+, 6+) | ||
List of Gold Compounds
Gold is a chemically inactive element but is an excellent conductor. Due to its softness, this precious metal is often hardened by being combined in an alloy with silver, copper, platinum, palladium, or other metals.
The measure of the gold content in such alloys is expressed in carats. Since one carat makes 1/24 part of the total weight of the gold alloy, the pure gold values 24 carats. In addition, when there is 75% gold in the alloy, the value of the god is 18 carats.
Gold–Halogen Compounds
- Bromo(tetrahydrothiophene)gold (I)
- Chloro(dimethyl sulfide)gold (I)
- Chloro(tetrahydrothiophene)gold (I)
- Chloro(triphenylphosphine)gold (I)
- Chloro-auric acid
- Gold halide
- Gold heptafluoride
- Gold monoiodide
- Gold triiodide
- Gold(I,III) chloride
- Gold(I) bromide
- Gold(I) chloride
- Gold(I) fluoride
- Gold(III) bromide
- Gold(III) chloride
- Gold(III) fluoride
- Gold(V) fluoride
- Tetra-bromo-auric acid
Gold–Sulfur Compounds
- Auranofin
- Aurothioglucose
- Bromo(tetrahydrothiophene)gold(I)
- Chloro(dimethyl sulfide)gold(I)
- Chloro(tetrahydrothiophene)gold(I)
- Disodium aurothiomalate
- Gold(I) sulfide
- Sodium aurothiomalate
- Sodium aurothio-sulfate
Gold Compounds
- Auranofin
- Aurothioglucose
- Aurotioprol
- Bromo(tetrahydrothiophene)gold(I)
- Caesium auride
- Chloro(dimethyl sulfide)gold(I)
- Chloro(tetrahydrothiophene)gold(I)
- Chloro(triphenylphosphine)gold(I)
- Chloroauric acid
- Disodium aurothiomalate
- Fulminating gold
- Gold
- Gold chalcogenides
- Gold cluster
- Gold halide
- Gold heptafluoride
- Gold monoiodide
- Gold salts
- Gold triiodide
- Gold(I,III) chloride
- Gold(I) bromide
- Gold(I) chloride
- Gold(I) sulfide
- Gold(III) bromide
- Gold(III) chloride
- Gold(III) fluoride
- Gold(III) hydroxide
- Gold(III) oxide
- Gold(III) sulfide
- Gold(V) fluoride
- Organogold chemistry
- Sodium aurothiomalate
- Sodium aurothiosulfate
- Tetrabromo-auric acid
- Tetraxenonogold(II)
- (2,4,6-Trimethylphenyl)gold
Gold(I) Compounds
- Auranofin
- Aurothioglucose
- Aurotioprol
- Bromo(tetrahydrothiophene)gold(I)
- Chloro(dimethyl sulfide)gold(I)
- Chloro(tetrahydrothiophene)gold(I)
- Chloro(triphenylphosphine)gold(I)
- Disodium aurothiomalate
- Gold monoiodide
- Gold(I) bromide
- Gold(I) chloride
- Gold(I) fluoride
- Gold(I) sulfide
- Honeaite
- Petzite
- Potassium dicyanoaurate
- Sodium aurothiomalate
- Sodium aurothiosulfate
- Uytenbogaardtite
Gold(III) Compounds
- Chloroauric acid
- Gold triiodide
- Gold(III) bromide
- Gold(III) chloride
- Gold(III) fluoride
- Gold(III) hydroxide
- Gold(III) oxide
- Gold(III) sulfide
- Sodium tetrachloroaurate
- Tetrabromoauric acid
5 Interesting Facts And Explanations
- Gold is often used in mythological narratives as an attribute or synonym for the Sun.
- In the old times, the transmutation of base metals into gold was the main goal and subject of chemical research for the alchemists.
- Salt waters contain large amounts of gold but in small concentrations. Namely, there are 4 grams of gold in a million tonnes of seawater, which makes all efforts for the collection of larger quantities of this noble metal futile.
- Tutankhamen, the Egyptian pharaoh of the 18th dynasty (r. c.1336-c.1327 BCE), had a golden sarcophagus and a death mask made out of 100 kg gold.
- 100% of the gold found in the Earth core consists of the gold-197 isotope.
Chemical Property and physical property of element Gold
Symbol of Gold: Au
Name: Gold
Atomic Number of Gold: 79
Atomic Mass of Gold: 196.96654
Uses of Gold: Very malleable. Used in electronics, jewelry and coins. It is a good reflector of infrared radiation, so a thin film of gold is applied to the glass of skyscrapers to reduce internal heating from sunlight.
Description of Gold: Heavy, silver-white metal, liquid at ordinary temperatures.
Melting Point of Gold:
Boiling Point of Gold:
Group of Gold: Transition Metal
Shells of Gold: 2,8,18,32,18,1
Orbitals of Gold: [Xe] 4f14 5d10 6s1
Valence of Gold: 1,3
Crystal Structure of Gold: Cubic: Face centered
Electro Negativity of Gold: 2.54
Covalent Radius of Gold: 1.34 Å
Ionic Radius of Gold: .85 (+3) Å
Atomic Radius of Gold: 1.79 Å
Atomic Volume of Gold: 10.2 cm³/mol
Name Origin of Gold: Anglo-Saxon: geolo (yellow); symbol from Latin: aurum (shining dawn).
Discovered of Gold By: Known to the ancients.
Year: Unknown
Location: Unknown
Pronounced of Gold: GOLD
Oxydation States of Gold: (3),1
Density of Gold: 19.32 g/cm³