Niobium vs Astatine

PropertyNb NiobiumAt Astatine
Atomic number4185
SymbolNbAt
NameNiobiumAstatine
Categorytransition-metalhalogen
Standard Atomic Weight92.90637 u210 u
Period56
Group517
Blocksp
Phase at STPsolidsolid
Electron configuration[Kr]5s14d4[Xe]6s24f145d106p5
Oxidation states[-3, -1, 0, 1, 2, 3, 4, 5][-1, 1, 3, 5, 7]
Electronegativity (Pauling)1.62.2
Electron affinity0.893 eV2.391 eV
Density8570 kg/m³7000 kg/m³
Melting point2476.85 °C301.85 °C
Boiling point4743.85 °C-273.15 °C
Discovery year18011940