Atomic number: 80

Symbol: Hg

Category: transition metal 

Density at 25°C: solid: density: 19.30 g·cm−3

Mercury is best known for the only metal to be liquid at room temperature. Although it looks intriguing, it is actually quite toxic. Mercury is mostly used for industrial chemical production but also in various medical uses in various alloys or compounds.

Mercury being poured at room temperature and won't solidify until about-38°C. image: adapted from wikipedia

Why is the symbol for mercury Hg? Well it comes from what it used to be called. It was called  hydrargyrum ; literally meaning water-silver , from Greek "hydr-" water and "argyros" silver.

Use, natural applications or common combinations: 

  • florescent lighting
  • amalgams for fillings(phasing out)
  • production of caustic soda
  • specialised high temp thermometers
  • used in vaccines as preservative as ethyl mercury which is excreted rapidly by the body.

Basic characteristics:

  • Standard atomic weight: 200.59(2)
  • Melting point: -38.83 °C
  • Boiling point: 356.73 °C
  • Radioactivity: all naturally stable. Some isotopes have very long half lives.