Mercury Element Facts (Hg or Atomic Number 80)

Mercury Facts

Mercury is a shiny, silver-colored, liquid metal. It is the only metallic element on the periodic table that is a liquid at room temperature and pressure. Mercury is atomic number 80 with element symbol Hg. Here is a collection of mercury element facts, including its properties, history, and uses.

Mercury is the only metal that is a liquid element at room temperature.
Mercury is the only metal that is a liquid element at room temperature. (Tavo Romann)

Fast Facts: The Element Mercury

  • Element Name: Mercury
  • Element Symbol: Hg
  • Atomic Number: 80
  • Atomic Weight: 200.592
  • Classification: Transition Metal or Post-Transition Metal
  • State of Matter: Liquid
  • Name Origin: The symbol Hg comes from the name hydrargyrum, which means “water-silver.” The name mercury comes from the Roman god Mercury, known for his swiftness.
  • Discovered By: Known before 2000 BCE in China and India
  • Electron Configuration: [Xe]4f145d106s2
  • Group: 12
  • Period: 6
  • Block: d-block


There is no official discoverer of the element mercury. It was known to the ancient Chinese and Hindus, who used it for medicinal purposes. Mercury was found in Egyptian tombs dated to 1500 BC.

How Mercury Got Its Name

Mercury’s element symbol “Hg” stands for its old name, hydrargyrum. Hydrargyrum means “water-silver.” The modern name refers to the element and to the Roman god Mercury, after whom the planet Mercury was named. This name for the element traces back to the age of alchemy, making mercury the only element to retain its alchemical name as its IUPAC name.

Mercury Uses

Historically, mercury was common in thermometers, manometers, barometers, sphymomanometers, switches and relays, float valves, and fluorescent lamps. However, mercury’s toxicity has led to replacement with other materials whenever possible, so it’s rare to find a mercury thermometer or sphymomanometer anymore. It’s still widely used in fluorescent bulbs and dental amalgam. It’s used to make the organometallic compound thimerosol, which preserves some vaccines, cosmetics, and contact lens solutions. The topical antiseptic merbromin or Mercurochrome remains in used in some countries. Mercury finds use in batteries, gold and silver mining, and making felt hats. While the element isn’t used much for these applications today, environmental clean-up from the past remains a concern. Commercially, mercury is used to make chlorine from sodium chloride and sodium hydroxide from metallic sodium. Mercury fulminate is used as a primer in small arms and pyrotechnics.

Mercury Isotopes

There are seven stable isotopes of mercury. The most abundant is mercury-202, which accounts for 29.86% of the natural element. There are numerous radioactive isotopes. The longest-lived radioisotope is mercury-194, which has a half-life of 444 years.

Sources of Mercury

Mercury is a very rare element in the Earth’s crust. It only accounts for about 0.08 parts per million of the crust’s mass. The main source of mercury is the mineral cinnabar. Cinnabar is mercuric sulfide. Mercury extraction from its ore requires heating the mineral and collecting the mercury vapor. Also it’s uncommon, sometimes mercury occurs free in nature. Mercury ores tend to occur near hot springs or volcanic regions.

Health Effects

Historically, mercury found use in medicine. It occurred in numerous medicines and disinfectants. Its use has declined, due to mercury toxicity. But, the element still occurs in some laxatives, eye drops, diuretics, nasal sprays, antiseptics, and ointments.

Mercury is absorbed through inhalation, across skin and mucous membranes, and by ingestion. Organic mercury compounds are the most toxic, but even the pure metal can cause acute and chronic poisoning. Mercury damages the brain, lungs, and kidneys. The first symptoms of poisoning include insomnia; irritability; lack of coordination; impaired vision, speech, and hearing; tremors; and impaired cognitive skills. Acute poisoning also rsults in coughing, chest pain, and lung tissue inflammation. Mercury poisoning is treated using chelating agents.

Interesting Mercury Element Facts

  • The reason mercury forms rounded liquid beads is because of its extremely high surface tension.
  • Mercury is highly volatile, so it disperses in air from open containers.
  • Mercury is extremely dense. It is one of the heavy metals.
  • Mercury usually has a +1 or +2 oxidation state, but sometimes it has a +4 oxidation state which makes it behave somewhat like a noble gas.
  • Most metals are excellent thermal and electrical conductors, but mercury is poor heat conductor and only a mild electrical conductor.
  • Most metals readily react with acids, but mercury doesn’t react with most of them.
  • Mercury forms amalgams with all metals except iron. So, iron is a good container choice for the liquid metal.
  • An electrical discharge can cause mercury to combine with the noble gases neon, krypton, argon, and xenon.
  • Mercury and aircraft don’t mix! Mercury reacts with the aluminum used in aircraft, forming an amalgam that interferes with the oxide layer that ordinarily protects aluminum. Basically, aluminum exposed to mercury corrodes, much like iron rusts.
  • The mercury-bearing mineral cinnabar is the source of the red pigment vemillion.
  • The phrase “mad as a hatter” comes from mercury poisoning of hat makers who used the metal in the felting process.
  • In the 19th century, “blue mass” was a mercury pill or syrup prescribed for toothaches, childbearing, depression, and constipation.
  • The 1937 World Exhibition in Paris featured a mercury fountain, which is on display today at the Fundació Joan Miró in Barcelona, Spain.

Physical Data

State at room temperature (300 K): Liquid
Appearance: Heavy silvery white metal
Density: 13.546 g/cc (20 °C)
Melting Point: 234.32 K (-38.83 °C or -37.894 °F)
Boiling Point: 356.62 K (356.62 °C or 629.77 °F)
Critical Point: 1750 K at 172 MPa
Heat of Fusion: 2.29 kJ/mol
Heat of Vaporization: 59.11 kJ/mol
Molar Heat Capacity: 27.983 J/mol·K
Specific Heat: 0.138 J/g·K (at 20 °C)

Atomic Data

Oxidation States: +2 , +1
Electronegativity: 2.00
Atomic Radius: 1.32 Å
Atomic Volume: 14.8 cc/mol
Ionic Radius: 1.10 Å (+2e) 1.27 Å (+1e)
Covalent Radius: 1.32 Å
Van der Waals Radius: 1.55 Å
First Ionization Energy: 1007.065 kJ/mol
Second Ionization Energy: 1809.755 kJ/mol
Third Ionization Energy: 3299.796 kJ/mol


  • Eisler, R. (2006). Mercury hazards to living organisms. CRC Press. ISBN 978-0-8493-9212-2.
  • Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
  • Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  • Norrby, L.J. (1991). “Why is mercury liquid? Or, why do relativistic effects not get into chemistry textbooks?”. Journal of Chemical Education. 68 (2): 110. doi:10.1021/ed068p110
  • Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.