Lutetium - Lu General Information Discovery Lutetium was discovered by G. Urbain in 1907 in Paris, France, and independently by C. James in the same year in New Hampshire, USA. Appearance Lutetium is a silvery-white metal, the hardest and densest of the lanthanides. Source In common with many other lanthanides, the principal source of lutetium is the mineral monazite, from which it is extracted with difficulty by reduction of the anhydrous fluoride by a metal from Group 1 or 2. Uses Lutetium has no practical value. Biological Role Lutetium has no known biological role, and has low toxicity. General Information Lutetium is one of the costliest of the 'rare earth' elements. It is relatively stable in air.

	Physical Information
	Atomic Number		71
	Relative Atomic Mass (12C=12.000)		174.97
	Melting Point/K		1963
	Boiling Point/K		3668
	Density/kg m-3		9840 (298K)
	Ground State Electron Configuration		[Xe]4f145d16s2
	Electron Affinity(M-M-)/kJ mol-1		-50

	Key Isotopes
	nuclide	175Lu	176Lu	177Lu
	atomic mass	174.9
	natural abundance	97.39%	2.61%	0%
	half-life	stable	2.2x1010 yrs	6.74 days

Other Information
Enthalpy of Fusion/kJ mol-1		19.2
Enthalpy of Vaporisation/kJ mol-1		428
Oxidation States
Lu+3

	Ionisation Energies/kJ mol-1
	M - M+	523.5
	M+ - M2+	1340
	M2+ - M3+	2022
	M3+ - M4+	4360
	M4+ - M5+
	M5+ - M6+
	M6+ - M7+
	M7+ - M8+
	M8+ - M9+
	M9+ - M10+