Holmium vs Erbium

PropertyHo HolmiumEr Erbium
Atomic number6768
SymbolHoEr
NameHolmiumErbium
Categorylanthanidelanthanide
Standard Atomic Weight164.93033 u167.259 u
Period66
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f11[Xe]6s24f12
Oxidation states[0, 1, 2, 3][0, 1, 2, 3]
Electronegativity (Pauling)1.231.24
Electron affinity0.338 eV0.312 eV
Density8800 kg/m³9070 kg/m³
Melting point1473.85 °C1528.85 °C
Boiling point2699.85 °C2867.85 °C
Discovery year18781843