Mercury

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Mercury
Chemical formula Hg
Atomic Number 80 
OTP appearance silver liquid 
Molar Mass(g/mol) 200.59 
Melting Point(°C) -38.829 
Boiling Point(°C) 356.7 
Density(g/cc) 13.53 
Coefficient of Thermal Expansion(×10-6 °C-1) 181
NFPA 704
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Mercury is one of the seven metals of antiquity. It is one of only two elements, and the only metal, that is liquid at OTP

Uses

Primary

  • With glass tubing:
    • Sprengel (vacuum) pump
    • Barometer
    • Thermometer
  • Electrolysis of more reactive metals (MO + Hg M + HgO, forced electrolytically)
  • Clemensen reduction with zinc and hydrochloric acid

Secondary

  • In place of barium oxide to isolate, store, and produce oxygen via a thermally weak oxide form (HgO)
  • Amalgamating noble metals
  • Conducting electricty (in a liquid, such as a tilt switch)

Hazards

Mercury vapor, organomercury compounds, and many inorganic mercury compounds are highly toxic.

Natural Sources

  • Elemental mercury does occur naturally, although it is extremely rare.
  • -sulfide occurs as the mineral cinnabar

Production

Extraction

from cinnabar

dry distillation of cinnabar mixed with calcium oxide at low read heat for some (2-12) hours produces mercury.[1]

4 HgS + 3 CaO
{
500°C 2-12hrs}
4 Hg + 3 CaS + SO3

dry distillation of cinnabar in the presence of oxygen produces sulfur dioxide and mercury vapor. The vapor is condensed into liquid mercury. cf. production of phosphorus. The sulfur dioxide can be used to produce sulfuric acid.

HgS + O2
{
≥580°C,}
SO2 + Hg(v)

dry distillation of cinnabar in the absence of oxygen produces molten sulfur and mercury vapor.

8 HgS
{
≥580°C,}
S8(l) + 8 Hg(v)

from -oxide

dry distillation of the -oxide gives mercury and gaseous oxygen

2 HgO
{
≥500°C}
2 Hg + O2

See Also

  • Cordero Mercury Mine near McDermitt, NV (BLM)

References

  1. Crookes, Sir William; Röhrig, Ernst Otto (1868) "A Practical Treatise on Metallurgy, Volumes 1-2"; pp505,524.