yttrium

Silver-grey, metallic element, atomic number 39, relative atomic mass 88.905. It is associated with and resembles the rare-earth elements (lanthanides), occurring in gadolinite, xenotime, and other minerals. It is used in colour-television tubes and to reduce steel corrosion.

The name derives from the Swedish town of Ytterby, near where it was first discovered in 1788. Swedish chemist Carl Mosander (1797-1858) isolated the element in 1843.