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56
Ba
137.33
Barium
Alkaline earth metals · Group 2 · Period 6
Atomic properties
| Atomic number | 56 |
|---|---|
| Symbol | Ba |
| Standard atomic weight | 137.33 |
| Classification | Alkaline earth metals |
| Group | 2 |
| Period | 6 |
| Block | s-block |
| Electron configuration | [Xe] 6s2 |
| Electronegativity (Pauling) | 0.89 |
| Common oxidation states | +2 |
Physical properties
| Phase at 20 °C | Solid |
|---|---|
| Density | 3.51 g/cm³ |
| Melting point | 727 °C |
| Boiling point | 1845 °C |
| Discovered | 1808 |
| CAS number | — |