Which metal is liquid at room temperature?
Quick answer
Mercury (chemical symbol Hg) is the only metal that’s liquid at ordinary room temperature. It melts at −38.8 °C (−37.9 °F) and boils at 356.7 °C. Its symbol comes from the Latin hydrargyrum, meaning “water-silver.” Mercury and its vapor are toxic, so it should never be handled directly.
Key facts
- Symbol
- Hg (from Latin hydrargyrum)
- Atomic number
- 80
- Melting point
- −38.8 °C (−37.9 °F)
- Density
- About 13.5 g/cm³, over 13 times water
Why mercury is liquid
In most metals, atoms share their outer electrons freely, holding them tightly together. Mercury’s electrons are held unusually close to the nucleus, partly due to effects from Einstein’s relativity at its high atomic number. As a result, mercury atoms bond only weakly to each other, so it melts at a very low temperature.
Metals that melt in your hand
Some metals are solid in a cool room but melt at temperatures just above:
| Element | Melting point | Notes |
|---|---|---|
| Mercury | −38.8 °C | Liquid at room temperature |
| Francium | About 27 °C (estimated) | Extremely rare and radioactive |
| Caesium | 28.5 °C | Reacts explosively with water |
| Gallium | 29.8 °C | Melts in your hand; safe to touch |
| Rubidium | 39.3 °C | Highly reactive |
The only other element liquid at room temperature is bromine, a non-metal.
So heavy, things float on it
Mercury is so dense that a steel bolt or even a lead weight will float on it.
Toxic metal
Mercury vapor and many mercury compounds are poisonous to the nervous system. For this reason:
- Mercury thermometers have been largely replaced by digital ones.
- The Minamata Convention (2013), named after a mercury poisoning disaster in Japan, aims to cut mercury use worldwide.
- The phrase “mad as a hatter” may relate to hat-makers poisoned by mercury used to treat felt.
Named after a planet and a god
Alchemists linked each metal with a planet. Fast-flowing quicksilver was named after Mercury, the swift messenger god and the fastest-orbiting planet. Learn about that planet’s heat in which planet is the hottest, and about another Latin-derived symbol in why gold’s symbol is Au.
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