Before a stomach X-ray, the doctor gives you a thick white liquid to drink — 'barium meal'. That's barium sulfate (BaSO₄), which makes organs visible on the image. The paradox: soluble barium compounds are a strong poison, yet insoluble sulfate is perfectly safe. It passes through the body without being absorbed.
Barium is also responsible for green fireworks. Its compounds emit bright green light when burning. And the name 'barium' comes from Greek 'barys' (heavy), because the mineral barite (BaSO₄) is unexpectedly heavy for a stone.
In industry, barium is an invisible workhorse. Over 75% of mined barite goes to produce drilling fluids for oil and gas wells. Heavy barite (density 4.5 g/cm³) creates pressure at the bottom of the well and prevents blowouts.
Concrete with barite filler shields against radiation: it lines the walls of X-ray rooms and nuclear labs. Barium ferrites are the basis of cheap permanent magnets for speakers and small motors.
Metallic barium is dangerous: it reacts with water and air, forming caustic Ba(OH)₂. Soluble compounds (BaCl₂, Ba(NO₃)₂) are highly toxic — lethal dose ~1 g for humans. Ba²⁺ ions block potassium channels in cells, causing convulsions, arrhythmia, and respiratory paralysis. Insoluble BaSO₄ is safe. Protective gloves and respirator are mandatory.
Barium colors flames bright green (524 nm). That's why green fireworks and signal flares are barium.
Soluble barium compounds are a strong poison (lethal dose of BaCl₂ ~1 g). But insoluble BaSO₄ is safe — it's drunk before X-rays.
Barite (BaSO₄) is so heavy (4.5 g/cm³) that 'barium' was named from Greek 'barys' — heavy. 75% of barite goes to drilling fluids.
Metallic barium served as a getter in vacuum tubes — it absorbed residual gases to create deep vacuum.
Concrete with barite shields against X-ray and gamma radiation. It lines the walls of X-ray rooms and nuclear labs.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
130Ba | 129.906321 | 0.11% | stable | — |
132Ba | 131.905061 | 0.10% | stable | — |
134Ba | 133.904508 | 2.42% | stable | — |
135Ba | 134.905689 | 6.59% | stable | — |
136Ba | 135.904576 | 7.85% | stable | — |
137Ba | 136.905827 | 11.23% | stable | — |
138Ba | 137.905247 | 71.70% | stable | — |
Electrolysis of barium hydroxide