Erbium 5. October 2015elementadmin ←Ho La↑ ↓Lu Tm→ 68 Er erbium 167.26 68 Er 3 Er litho Erbium ∙ erbium ∙ erbio ∙ erbiogroup III: R2O3 melting point: 1529°C boiling point: 2868°C density: 9.05 g/cm³ ☢ radioisotopes:Er-169 (T1/2=9.4 d) medical