99 Es

Einsteinium

Actinide
Atomic number99
CategoryActinide
Atomic mass252
Electron configuration[Rn]5f¹¹ 7s²
Oxidation states+3
Electronegativity1.3
Melting point860 °C
Boiling point996 °C
Density8.84 g/cm³
Crystal structureFace-centred cubic
Period7
Blockf
Discovered1,952
Crustal abundance0 ppm

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