Periodic Table of Elements




In 1774, Carl Wilhelm Scheele showed that barium oxide is a distinct compound. Barium was first isolated by Sir Humphry Davy, an English chemist, in 1808 through the electrolysis of molten barium salts.

Name: Barium
Symbol: Ba
Atomic number: 56
Atomic weight: 137.33
State: solid
Group, period, block: 2, 6, s
Color: silvery gray
Classification: alkaline earth metals
Electron configuration: 6s2

Physical properties

Density: 3.51 g/cm-3
Melting point: 1000 K, 727 C, 1341 F
Boiling point: 2170 K, 1897 C, 3447 F

Atomic properties

Oxidation states: +2
Electronegativity: 0.89 (Pauling scale)
Ionization energies: 1st: 502.9 kJmol-1
Covalent radius: 21511 pm
Van der Waals radius: 268 pm
  • Ba
  • Electron Configuration


There are seven naturally occurring isotopes of barium exist, 130Ba, 132Ba, 134Ba, 135Ba, 136Ba, 137Ba, and <138Ba.