Mercury is the only naturally occurring metal that is liquid at ordinary room temperature.
It is a chemical element with the symbol Hg and atomic number 80. Mercury’s silvery appearance and unusual liquid state made it useful in historical thermometers, barometers, switches, and other instruments. Its freezing point is about −38.83 °C, while its boiling point is about 356.73 °C, giving it a broad liquid range under everyday conditions.
The element occurs naturally in minerals, especially cinnabar, a mercury sulfide ore. Ancient civilizations used cinnabar as a pigment and obtained mercury from it by heating. Mercury is toxic, and exposure can harm the nervous system and other organs, so many traditional uses have been reduced or replaced.
Bromine is also liquid at room temperature, but it is a nonmetal. Gallium and cesium are metals that can melt near room temperature, yet they are normally solid in a typical room. Mercury’s liquid state is therefore a distinctive elemental property, not a description of all liquid metals under every condition.