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Element · Eu

Europium

The rare earth that put red on television screens and now helps prove banknotes are genuine.

Europium is the most reactive of the rare earths, igniting in air and reacting with water much like calcium. It is also the least abundant of the group in most ores, which historically made it the limiting element in phosphor production.

What makes it valuable is luminescence. Europium ions emit at very specific wavelengths with high efficiency — trivalent europium gives a saturated red, divalent europium a blue — and the emission is largely unaffected by the host material, which is unusual and extremely useful.

Uses

Europium-doped phosphors produced the red in colour cathode-ray television, and the arrival of a bright, efficient red phosphor is what made colour television commercially viable.

The same chemistry now provides red and blue components in fluorescent lamps and white LEDs. Europium phosphors are printed into euro banknotes as an anti-counterfeiting measure, visible under ultraviolet light. Europium is also used as a neutron absorber in reactor control and as a luminescent label in medical diagnostic assays.

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 red and blue phosphor components in lamps and white LEDs

is produced by

  • Rare earth separation — process · a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller

is found in

  • Phosphor — material · red and blue, and the reason a colour television picture and a fluorescent lamp both changed abruptly when it became available

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 Europium 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

  • Europium → is produced by (a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller) → Rare earth separation → takes as input (the principal ore of the light rare earths, carrying all of them together) → Bastnäsite
  • Europium → is produced by (a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller) → Rare earth separation → takes as input (the other feed alongside bastnäsite, bringing thorium into the residues with it) → Monazite
  • Europium → is produced by (a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller) → Rare earth separation → takes as input (the heavy rare earth feed, where monazite and bastnäsite bring the light ones) → Xenotime

Downstream — what it becomes

  • Europium → is used as (the red and blue phosphor components in lamps and white LEDs) → Lighting