Rare-earth element

Any of the fifteen lanthanides plus scandium and yttrium

The rare-earth elements (REE), also called rare-earth metals, or rare earths, are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. The 15 lanthanides (or lanthanoids), along with scandium, and yttrium, are usually included as rare earths. Compounds containing rare-earth elements have diverse applications in electrical and electronic components, lasers, glass, magnetic materials, and industrial processes.

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