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Material World
Element · Gd

Gadolinium

A rare earth that absorbs neutrons better than almost anything and makes MRI scans readable.

Gadolinium is a silvery rare earth with two properties that are both consequences of its half-filled electron shell: it has the highest thermal neutron capture cross-section of any stable element, and it is strongly paramagnetic.

It also has a Curie point close to room temperature, meaning it loses its magnetism when slightly warmed — a curiosity that is being pursued seriously as the basis of magnetic refrigeration, which would cool without compressors or refrigerant gases.

Uses

Gadolinium chelates are the standard contrast agent for magnetic resonance imaging. Injected before a scan, they shorten the relaxation time of nearby water protons and make blood vessels, tumours and inflammation stand out. The metal ion is toxic in free form, so it is bound in a molecular cage designed to hold it until excretion.

Its neutron appetite makes it a reactor shutdown material and a neutron detector component. Gadolinium is also added to steels and alloys to improve workability, and gadolinium garnets are used in microwave devices and magneto-optical applications.

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

  • Medical imaging — application · gadolinium chelates for magnetic resonance

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 · in X-ray intensifying screens, which is the use gadolinium is actually bought for

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 Gadolinium 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

  • Gadolinium → 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
  • Gadolinium → 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
  • Gadolinium → 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