Selenium
Elemental State Se
Electron Configuration 1s22s22p63s23p63d104s24p4
First Ionization Potential 9.752 eV
Electron Affinity 2.021 eV
Z* 8.287 (Clementi-Raimondi)
Pauling Electronegativity 2.55
Covalent Radius 1.16 Å
Metallic Radius  
Ionic Radius 1.84 Å Se2– coordination number = 6
van der Waal's Radius 1.90 Å
Melting Point 221 oC
Boiling Point 685 oC
Density 4.79 g/cm3
Other Properties