Erbium vs Curium

PropertyEr ErbiumCm Curium
Atomic number6896
SymbolErCm
NameErbiumCurium
Categorylanthanideactinide
Standard Atomic Weight167.259 u247 u
Period67
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f12[Rn]7s25f76d1
Oxidation states[0, 1, 2, 3][3, 4, 5, 6]
Electronegativity (Pauling)1.241.3
Electron affinity0.312 eV0.277 eV
Density9070 kg/m³1.351000e+4 kg/m³
Melting point1528.85 °C1344.85 °C
Boiling point2867.85 °C3126.85 °C
Discovery year18431944