Yttrium (Y) is a silvery-white rare-earth element of group III of the periodic table; it is used in alloys and as a "getter" to help evacuate electron tubes. First isolated in 1828, yttrium is found in monzate sand, bastnaesite, and gadolinite; it was also found in lunar rock samples collected by the Apollo 11 mission.

 

A red phosphor (yttrium oxide or vanadate excited by europium) is used in color televisions, and yttrium-iron garnets are used in radar.

 

The commonest isotope of yttrium is ⁸⁹Y (100%). Yttrium-90 is an artificial radioactive isotope used in radiotherapy.

 

atomic number	39
relative atomic mass	88.906
relative density	4.47
melting point	1,523°C (2,773°F)
boiling point	3,337°C (6,039°F)