Zirconium vs Niobium

PropertyZr ZirconiumNb Niobium
Atomic number4041
SymbolZrNb
NameZirconiumNiobium
Categorytransition-metaltransition-metal
Standard Atomic Weight91.224 u92.90637 u
Period55
Group45
Blockss
Phase at STPsolidsolid
Electron configuration[Kr]5s24d2[Kr]5s14d4
Oxidation states[1, 2, 3, 4][-3, -1, 0, 1, 2, 3, 4, 5]
Electronegativity (Pauling)1.331.6
Electron affinity0.426 eV0.893 eV
Density6520 kg/m³8570 kg/m³
Melting point1854.85 °C2476.85 °C
Boiling point4408.85 °C4743.85 °C
Discovery year17891801