Mercury
Element 80 · Transition Metal
Mercury is unique: the only metal liquid at room temperature, flowing as dense silvery droplets that bead up instead of wetting surfaces. It expands uniformly with heat, which made it the classic thermometer fluid for centuries.
Its beauty hides real danger. Mercury and its compounds attack the nervous system, and spills or vapors demand professional cleanup — this is why thermometers, dental amalgam, and many industrial uses have been phased out. It still appears in fluorescent lamps and specialized instruments, always with strict handling rules.
Key facts
| Atomic number | 80 |
|---|---|
| Atomic weight | 200.59 |
| Category | Transition Metal |
| Group / Period | 12 / 6 |
| Block | d |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 |
| Common oxidation states | +2, +1 |
| State at STP | Liquid |
| Electronegativity | 2.00 |
| Density | 13.53 g/cm³ |
| Melting point | -38.83 °C |
| Boiling point | 356.73 °C |
Occurrence
Mercury is mined from cinnabar (mercury sulfide), with historic deposits in Spain, Italy, and China. It also cycles through the environment from coal burning and volcanoes.
Applications
Fluorescent lamps
Scientific instruments (historic thermometers)
Chlor-alkali chemical production
Dental amalgam (declining)
Common compounds
- mercury(II) oxide
- mercury(II) chloride
- mercury sulfide
Mercury is the only metal that stays liquid at room temperature — alchemists called it quicksilver, and it readily forms alloys called amalgams with gold and silver.
Data source: IUPAC standard atomic weights 2021