It glows pale blue in the dark. That magical light captivated Marie Curie when she isolated a new element from tons of uranium ore in 1898. Radium became the symbol of radioactivity — and one of the most dangerous substances humanity has ever known.
In the 1920s, radium was everywhere: in watches, toothpaste, tonic drinks, and even chocolate. People believed it cured everything. But the tragedy of the 'Radium Girls' — factory workers who licked brushes dipped in radium paint — revealed the truth. Radium kills. Today its use is strictly limited.
Radium is an alkaline earth metal, chemically similar to barium and calcium. A fresh cut is shiny and silvery, but instantly darkens in air. The main danger: the body mistakes radium for calcium and builds it into bones, where alpha radiation destroys bone marrow for years.
The most stable isotope — radium-226 — has a half-life of 1,600 years. It's part of the uranium-238 decay chain and is the source of radon — a radioactive gas that accumulates in the basements of buildings.
Radium is extremely dangerous. It emits alpha, beta, and gamma radiation simultaneously. The body treats it like calcium and builds it into bones, where it destroys bone marrow, causes cancer, and leads to jaw necrosis. Radium-226 has a half-life of 1,600 years. Any direct contact is prohibited. Work is only permitted in sealed gloveboxes with lead shielding.
Radium glows pale blue in the dark. This isn't phosphorescence — its own radiation ionizes surrounding air, making it glow.
Marie Curie processed 8 tons of uranium ore to obtain 1 gram of pure radium. She received two Nobel Prizes for her work.
Radium is so radioactive it heats itself up. One gram of Ra-226 releases 0.1 watts of heat — enough to feel warm to the touch.
In the 1920s, factory workers painted watch dials with radium paint and licked their brushes for precision. Dozens died from bone cancer — they're called the 'Radium Girls.'
The Radium Girls' tragedy changed the world: their lawsuits created the first laws protecting workers from radiation exposure.
Radium-226 has a half-life of 1,600 years. The sample Marie Curie once held in her hands is still more than 90% radioactive today.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
223Ra☢ | 223.018502 | synthetic | 11.43 days | α |
224Ra☢ | 224.020212 | synthetic | 3.6319 days | α |
226Ra☢ | 226.025410 | synthetic | 1600 years | α |
228Ra☢ | 228.031070 | synthetic | 5.75 years | β− |
Analysis of pitchblende