Mercury

Description

The only metal that is liquid at room temperature — and a potent neurotoxin.

Physical Properties

Atomic Properties

Discovery & History

Known since antiquity

Mercury has been known for at least 3,500 years. It has been found in Egyptian tombs from around 1500 BCE, and cinnabar was used as a red pigment even earlier. Chinese, Indian and Greek writers described the liquid metal and how to obtain it by heating cinnabar.

Quicksilver and hydrargyrum

The metal was called quicksilver, meaning living silver, because it runs like a liquid. Its symbol, Hg, comes from the Latin hydrargyrum, from the Greek for water-silver, and its modern name from the Roman god and the planet Mercury, which alchemists linked with the metal.

An element, and a danger

In 1759 Joseph Adam Braun in St Petersburg froze mercury for the first time, showing that it was a metal like the others, and Antoine Lavoisier listed it as an element in 1789. Its toxicity was long known among miners and hat makers, and the methylmercury poisoning at Minamata led to the Minamata Convention, adopted in 2013.

Isotopes

Data: IAEA Nuclear Data Section, LiveChart of Nuclides, ground-state evaluations, retrieved October 10, 2026. Abundance is the share of atoms in the natural element; a dash means the isotope has no standard natural abundance.

Applications & Uses

Uses being phased out

The Minamata Convention on Mercury, in force since 2017, requires countries to phase out most mercury-added products, including thermometers, blood pressure gauges, most batteries and switches, and many fluorescent lamps, and parties have agreed to end the manufacture, import and export of dental amalgam by 2034. The European Union banned most uses of dental amalgam from 2025.

Remaining uses

Gold mining: artisanal and small-scale gold miners use mercury to bind gold. This is the largest use of mercury worldwide and the largest source of mercury pollution.

Chemical industry: some chlor-alkali plants still use mercury cells, and mercury catalysts are used to make vinyl chloride from coal-derived acetylene, mainly in China.

Lighting and instruments: some fluorescent and specialty lamps, and laboratory and calibration equipment.

Medicine: thiomersal, a mercury compound, preserves some multi-dose vaccines.

In the history of science

Mercury's high density made it the liquid of choice for barometers, from Evangelista Torricelli's experiment in 1643, and for manometers, which is why blood pressure is still measured in millimeters of mercury.

Abundance