Thulium 5. October 2015elementadmin ←Er La↑ ↓Lu Yb→ 69 Tm thulium 168.93 69 Tm 3 Tm litho Thulium ∙ thulium ∙ tulio ∙ tuliogroup III: R2O3 melting point: 1545°C boiling point: 1950°C density: 9.33 g/cm³