Name: barium. Molecular formula: Ba.  Molecular weight: 137.33. Melting point: 725 ℃. Density: The relative density (water = 1) is 3.55. Solubility: Not soluble in mineral acids, insoluble in ordinary solvent. Stability: unstable. Appearance and properties: A shiny silver metal, yellow when nitrogen-containing, slightly malleable. Hazard label: 10 (combustible when wet). Mainly application: Used to produce barium salt, also used for getter, nodulizer and degasifying alloy.