Name Mercury
Symbol Hg
Atomic Number 80
Atomic Mass 200.59 atomic mass units
Number of Protons 80
Number of Neutrons 121
Number of Electrons 80
Melting Point -38.87° C
Boiling Point 356.58° C
Density 13.456 grams per cubic centimeter
Normal Phase Liquid
Family Transitions Metals
Period Number 6
Cost Unavailable



Origin of Name After the Roman god and the planet, Mercury
The symbol, Hg, comes from hydrargyrum, a Latinized form of the Greek word Υδραργυρος (hydrargyros), which means water combined with silver
Date and Place of Discovery Known to the ancients
Discovered by Unknown
Common Compounds
Interesting facts
  • It was known to the ancient Chinese and Hindus and was found in Egyptian tombs dating back to 1500 B.C.
  • In ancient days it was thought to prolong life, heal fractures, and promote good health.
  • It is extremely rare and not found easily in the earth's crust.
  • Its symbol, Hg, stands for water combined with silver since it is liquid like water but has a silvery sheen.
  • It is found in fish and shellfish because of their natural tendency to accumulate it in their bodies.
  • It is a neurotoxin that accumulates in soft tissues and bone.
  • It is the main ingredient in dental amalgams, but there is a controversy whether it is safe or not.  The American Society of Dental Surgeons doesn't feel it is a health threat, but there is controversy in the world.
  • Alexander Calder built a mercury fountain for the Spanish Pavilion at the 1937 World's Fair in Paris. The fountain is now on display at the Fundació Miró in Barcelona.
Common Uses
  • Thermometers used to measure high temperatures.  In the United States it is illegal to produce or sell thermometers with mercury that are used to measure fevers because of the high toxicity of mercury.
  • Sphygmomanometers
  • Barometers
  • Diffusion pumps
  • Coulometers
  • Electron tubes
  • Mercury arc rectifiers
  • Mercury vapor lams
  • Advertising signs
  • Fluorescent lamps
  • Coolant in nuclear reactors
  • Gold and silver refinement
  • Electrochemistry
  • Mercury switches
  • Electrolysis
  • Batteries
  • Catalysts
  • Insecticides
  • Dental amalgams
  • Liquid Mirror telescopes
  • Preservative in vaccines


Photo Courtesy of
Chemical Elements
Jefferson Labs
Web Elements

Mercury Atomic Structure Elements by Name Elements by Number