Gadolinium vs Erbium

PropertyGd GadoliniumEr Erbium
Atomic number6468
SymbolGdEr
NameGadoliniumErbium
Categorylanthanidelanthanide
Standard Atomic Weight157.25 u167.259 u
Period66
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f75d1[Xe]6s24f12
Oxidation states[0, 1, 2, 3][0, 1, 2, 3]
Electronegativity (Pauling)1.21.24
Electron affinity0.132 eV0.312 eV
Density7900 kg/m³9070 kg/m³
Melting point1312.85 °C1528.85 °C
Boiling point3272.85 °C2867.85 °C
Discovery year18861843