Lutetium

Symbol: Lu
Date of discovery: 1907
Name origin: from Lutetia
Appearance: silvery
Discoverer: Georges Urbain
Obtained from: gadolinite, xenotime

Melting point: 1656 K
Boiling point: 3402 K
Density[kg/m³]: 9.85
Molar volume: 17.78 × 10^-6 m³/mol
Protons/Electrons: 71
Neutrons: 104
Shell structure: 2,8,18,32,9,2
Electron configuration: [Xe]4f145d16s2
Oxidation state: 3
Crystal structure: hexagonal

Found with almost all other rare earth metals, but never by itself, lutetium is extremely difficult to isolate. Consequently, it is one of the most expensive metals, costing about six times as much per gram as gold. Not surprisingly, lutetium has no large-scale practical uses. Stable lutetium nuclides can be used as catalysts in cracking, alkylation, hydrogenation, and polymerization processes. It is used as a catalyst in refineries for petroleum cracking. Lutetium aluminum garnet has been proposed for use as a lens material in high refractive index immersion lithography.