Thulium vs Ytterbium

Side-by-side comparison of Thulium (Tm, element 69) and Ytterbium (Yb, element 70) by atomic structure and physical properties.

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PropertyTm Thulium Yb Ytterbium
Atomic number6970
SymbolTmYb
NameThuliumYtterbium
Categorylanthanidelanthanide
Standard Atomic Weight168.93422 u173.045 u
Period66
GroupN/AN/A
Blockff
Phase at STPSolidSolid
Electron configuration[Xe]4f136s2[Xe]4f146s2
Oxidation states[0, 1, 2, 3][0, 1, 2, 3]
Electronegativity (Pauling)1.25N/A
Electron affinity1.029 eV-0.02 eV
Density9320 kg/m³6900 kg/m³
Melting point1544.85 °C818.85 °C
Boiling point1949.85 °C1195.85 °C
Discovery year18791878

Key Differences

PropertyTm ThuliumYb Ytterbium
Standard Atomic Weight168.93422 u ↓ lower173.045 u ↑ higher
Density9320 kg/m³ ↑ higher6900 kg/m³ ↓ lower
Melting point1544.85 °C ↑ higher818.85 °C ↓ lower
Boiling point1949.85 °C ↑ higher1195.85 °C ↓ lower
Electron affinity1.029 eV ↑ higher-0.02 eV ↓ lower
Electron configuration[Xe]4f136s2 [Xe]4f146s2
Discovery year1879 1878