ERBIUM

TRANSITION ELEMENT: LANTHANIDE

Atomic number:	68
Group numbers:	3
Period:	6
Electronic configuration:	[Xe] 4f¹² 6s²
Formal oxidation number:	+3
Electronegativities:	1.24
Atomic radius / pm:	173.4
Relative atomic mass:	167.259(3)

Erbium was discovered by Carl Gustaf Mosander (SE) in 1843. Named after Ytterby, a village in Sweden. It is a soft, malleable, silvery metal that reacts slowly with water and dissolves in acids. Metal ignites and burns readily. Erbium is found with other heavier rare earths in xenotime and euxenite. Erbium oxide is used in ceramics to obtain a pink glaze. There are also a few uses in the nuclear industry and as an alloying agent for other exotic metals. The price of 99.9 % pure erbium pieces is 232.60 € for 50 g.

PHYSICAL PROPERTIES
Density / g dm^-3:	9066	(298 K)
Molar volume / cm³mol^-1:	18.45	(298 K)
Electrical resistivity / µΩcm:	107	(20 °C)

THERMAL PROPERTIES
Thermal conductivity / W m^-1K^-1:	14.3
Melting point / °C:	1529
Boiling point / °C:	2868
Heat of fusion / kJ mol^-1:	17.2
Heat of vaporization / kJ mol^-1:	280
Heat of atomization / kJ mol^-1:	318.32

IONIZATION ENERGIES
First ionization energy / kJ mol^-1:	589.31
Second ionization energy / kJ mol^-1:	1151.08
Third ionization energy / kJ mol^-1:	2194.09

ABUNDANCE OF ELEMENT
in the atmosphere / ppm:	-
in the Earth's crust / ppm:	2.2
in the oceans / ppm:	0.0000002

CRYSTALLOGRAPHIC DATA
Crystal structure:	hexagonal
Unit-cell dimensions / pm:	a=355.88, c=558.74
Space group:	P6₃/mmc

ISOTOPES
Isotope	Relative atomic mass	Mass percent (%)
¹⁶²Er	161.928775(4)	0.14(1)
¹⁶⁴Er	163.929197(4)	1.61(2)
¹⁶⁶Er	165.930290(3)	33.6(2)
¹⁶⁷Er	166.932045(3)	22.95(15)
¹⁶⁸Er	167.932368(3)	26.8(2)
¹⁷⁰Er	169.935460(3)	14.9(2)