rare earth

listen to the pronunciation of rare earth
English - English
naturally occurring oxides of the lanthanide metals; they are widely distributed in relatively small concentrations and are used in glassmaking, ceramic glazes etc
any element of the lanthanide series (atomic numbers 57 through 71)
rare earth element
Any of a group of soft, lustrous, sometimes magnetic metals that form trivalent salts; they include the lanthanides plus yttrium, scandium, thorium and sometimes zirconium
rare earth elements
plural form of rare earth element
rare earth magnet
Strong, permanent magnets that are made from alloys of rare earth elements, are much stronger than ferrite or alnico magnets, and are extremely brittle
rare earth metal
Any of a large class of chemical elements including scandium (atomic number 21), yttrium (39), and the 15 elements from 57 (lanthanum) to 71 (see lanthanides). The rare earths themselves are pure or mixed oxides of these metals, originally thought to be quite scarce; however, cerium, the most plentiful, is three times as abundant as lead in the Earth's crust. The metals never occur free, and the pure oxides never occur in minerals. These metals are similar chemically because their atomic structures are generally similar; all form compounds in which they have valence 3, including stable oxides, carbides, and borides
rare earths
plural form of rare earth
rare-earth magnet
A neodymium magnet or NIB magnet (also, but less specifically, called a rare-earth magnet) is a powerful magnet made of a combination of neodymium, iron, and boron — Nd2Fe14B
rare earth
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