a silvery metallic element occurring in monazite and gadolinite and used in various alloys, in lasers, and as a catalyst. Symbol: Y; atomic no: 39; atomic wt: 88.90585; valency: 3; relative density: 4.469; melting pt: 1522°C; boiling pt: 3338°C
A silvery metallic element found in the same ores as elements of the lanthanide series. Yttrium is used to strengthen magnesium and aluminum alloys, to provide the red color in color televisions, and as a component of various optical and electronic devices. Atomic number 39; atomic weight 88.906; melting point 1,522°C; boiling point 3,338°C; specific gravity 4.45 (25°C); valence 3. See Periodic Table.