All practice pages/Interatomic theory/Elements
Element 65, a lanthanide
A rare earth from the Ytterby quarry whose compounds glow a vivid green.
Period 6, in the lanthanide row set below the main table. The other lanthanides are tinted, and every cell opens its own article.
Like the other lanthanides, it gives up three electrons to form the Tb³⁺ ion in most of its compounds.
One of the rarer rare earths, found in xenotime, monazite and the ion-adsorption clays of southern China.
Carl Gustaf Mosander found it in 1843 in yttria from Ytterby, together with erbium, and both were named after the village. The two names were later swapped by mistake, and the swap stuck.
Green phosphors in fluorescent lamps and screens; Terfenol-D, an alloy that changes shape in a magnetic field and drives sonar and precision actuators; and small additions to neodymium magnets that must work in hot motors.