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Material World
Element · Hg

Mercury

The only metal that is liquid at room temperature, and the one whose applications have been withdrawn one by one.

Mercury's liquidity at ordinary temperatures made it uniquely useful for two centuries: thermometers, barometers, electrical switches, and — most consequentially — the amalgamation process for extracting gold and silver from ore.

It is also a potent neurotoxin whose vapour is absorbed through the lungs and whose organic compounds bioaccumulate up food chains. The Minamata Convention, named after the Japanese city where industrial methylmercury discharge caused mass poisoning, has phased out most remaining uses. Artisanal gold mining remains the largest source of mercury released by humans.

Name origin

Named for the planet and the Roman messenger god, after its mobility. Its symbol Hg comes from hydrargyrum, 'water-silver'.

Uses

Mercury's uses are being systematically eliminated under the Minamata Convention, and the story of the element now is mostly one of substitution.

It has left thermometers, blood pressure cuffs, and most switches and batteries. Fluorescent lighting still depends on a small mercury vapour dose to produce the ultraviolet that excites the phosphor, and that use is declining as LEDs replace tubes. Its most damaging current use is artisanal gold mining, where mercury amalgamates gold from ore and is then burned off into the air.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is used as

  • Lighting — application · the vapour discharge in fluorescent tubes, now being phased out

is extracted from

  • Cinnabar — mineral · essentially the only ore; roasting it in air releases the metal as vapour, which is condensed Wikidata

is produced by

  • Roasting — process · roasting cinnabar drives the mercury off as a vapour, which is condensed — one of the few metals won directly by heating its ore in air

is a component of

  • Amalgam — alloy · 40–55% · the defining constituent — an amalgam is by definition mercury with something dissolved in it

is found in

Sources

  • Material World
    Our own writing
  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
  • PubChem
    US National Library of Medicine · Mixed — aggregated third-party content, rights retained by depositors
  • NIST — National Institute of Standards and Technology
    United States Department of Commerce · US Government work — public information, credit requested

Questions this page answers

Where it comes from, and what it becomes

Follow Mercury back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Mercury → is produced by (roasting cinnabar drives the mercury off as a vapour, which is condensed — one of the few metals won directly by heating its ore in air) → Roasting → takes as input (a copper sulfide; roasting drives off the sulfur that would otherwise prevent reduction) → Chalcopyrite
  • Mercury → is extracted from (essentially the only ore; roasting it in air releases the metal as vapour, which is condensed) → Cinnabar
  • Mercury → is produced by (roasting cinnabar drives the mercury off as a vapour, which is condensed — one of the few metals won directly by heating its ore in air) → Roasting → takes as input (roasted for its sulfur as much as for its iron) → Pyrite
  • Mercury → is produced by (roasting cinnabar drives the mercury off as a vapour, which is condensed — one of the few metals won directly by heating its ore in air) → Roasting → takes as input (roasted to the oxide, the sulfur going to an acid plant rather than the air) → Galena
  • Mercury → is produced by (roasting cinnabar drives the mercury off as a vapour, which is condensed — one of the few metals won directly by heating its ore in air) → Roasting → takes as input (roasted to zinc oxide before reduction or electrolytic winning) → Sphalerite
  • Mercury → is produced by (roasting cinnabar drives the mercury off as a vapour, which is condensed — one of the few metals won directly by heating its ore in air) → Roasting → takes as input (roasted in air; the mercury leaves as vapour rather than staying behind as an oxide) → Cinnabar

These are the most distinct paths back. Mercury can be traced through others besides.

Downstream — what it becomes

  • Mercury → is used as (the vapour discharge in fluorescent tubes, now being phased out) → Lighting
  • Mercury → is a component of (the defining constituent — an amalgam is by definition mercury with something dissolved in it) → Amalgam