Praseodymium vs Erbium

PropertyPr PraseodymiumEr Erbium
Atomic number5968
SymbolPrEr
NamePraseodymiumErbium
Categorylanthanidelanthanide
Standard Atomic Weight140.90766 u167.259 u
Period66
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f3[Xe]6s24f12
Oxidation states[0, 1, 2, 3, 4, 5][0, 1, 2, 3]
Electronegativity (Pauling)1.131.24
Electron affinity0.962 eV0.312 eV
Density6770 kg/m³9070 kg/m³
Melting point930.85 °C1528.85 °C
Boiling point3519.85 °C2867.85 °C
Discovery year18851843