Symbol Er Atomic radius: pm 173 Fusion: kJ/Mole 19.9
Name Erbium Ionic radius: pm (+3)100 Boiling point: C 2868
Atomic number 68 Electron affinity - Melting point: C 1529
Atomic weight 167.3 1st  ion potential 6.11 Specific Heat Cap: J/(g K) 0.17
Classification Trans metal Natural form Solid Thermal Cond: W/(cm K) 0.15
Configuration [Xe]4f126s2 Crystal structure Hex Electrical Cond 0.0117
Oxidation states 3 Density 9.07 Abundance: mg/kg-crust 3.5
Electronegativity 1.24 Vaporization: kJ/Mole 293.0    
Erbium was discovered in 1843 as an oxide by C.G. Mosander. Uses - alloys, photographic filter, colorant in glasses and porcelain enamel glazes