Radium (Ra)
Isotopes of Radium
| Isotope | Atomic Mass | Half-life | Mode of Decay | Nuclear Spin | Nuclear Magnetic Moment |
| Ra-223 | 223.018497 | 11.435 days | α to Rn-219; C-14 | 3/2 | 0.271 |
| Ra-224 | 224.020202 | 3.66 days | α to Rn-220; C-12 | 0 | No data available |
| Ra-225 | 225.023603 | 14.90 days | β- to Ac-225 | 3/2 | -0.734 |
| Ra-226 | 226.025403 | 1599 years | α to Rn-222; C-14 | 0 | No data available |
| Ra-227 | 227.029170 | 42 minutes | β- to Ac-227 | 3/2 | -0.404 |
| Ra-228 | 228.031063 | 5.76 years | β- to Ac-228 | 0 | No data available |
Radium was discovered in 1898 by Pierre and Marie Curie. It takes its name from the Latin word radius, meaning “ray.”
The chemistry of radium is very similar to that of barium. The metal forms a number of salts in its +2 valence state, the only valence state typical of alkaline earth metals. The few salts that are of commercial use include chloride (RaCl2), bromide (RaBr2) and sulfate (RaSO4).
Radium was once an additive in products such as toothpaste, hair creams and even food items, due to its supposed curative powers. Such products soon were prohibited by authorities in many countries after it was discovered they could have serious adverse health effects. Mixed with phosphors in minute proportion, radium has also been used to make luminous paints and watch dials — these uses were discontinued in the 1960s.
Radium salts have several applications. Used historically in cancer treatment for destroying malignant tumors, they have been replaced by more readily available and low-cost radioisotopes such as Cobalt-60. Radium's gamma radiation is used for irradiating metals to detect fractures in welding. Radium-226 is a source material for producing Radon-222 in radiotherapy treatments (Radon-222 is safer to use because of its much shorter half-life of 3.8 days).
The radiation from radium can cause lung cancer, osteogenic sarcoma, blood dyscrasias and injury to skin. Inhalation, ingestion, skin contact or bodily exposure to radium or any of its salts must be avoided.
Properties of Radium
| Name | Radium |
| Symbol | Ra |
| Atomic number | 88 |
| Atomic weight | 226 |
| Standard state | Solid at 298 °K |
| CAS Registry ID | 7440-14-4 |
| Group in periodic table | 2 |
| Group name | Alkaline earth metal |
| Period in periodic table | 7 |
| Block in periodic table | s-block |
| Color | Metallic |
| Classification | Metallic |
| Melting point | 700 °C |
| Boiling point | 1737 °C |
| Thermal conductivity | 19 W/(m·K) |
| Electrical resistivity | 100 x 10-8 Ω·m |
| Electronegativity | 0.9 |
| Heat of vaporization | About 125 kJ·mol-1 |
| Heat of fusion | About 8 kJ·mol-1 |
| Density of solid | 5.00 g/cm3 |
| Electron configuration | [Rn]7s2 |
| Oxidation state | +2 |
Research
- Regolith evolution on the millennial timescale from combined U–Th–Ra isotopes and in situ cosmogenic 10Be analysis in a weathering profile (Strengbach catchment, France)
- Coastal ocean and shelf-sea biogeochemical cycling of trace elements and isotopes: lessons learned from GEOTRACES
- Natural gas industry wastewater pollution may linger for years
- Increased fluxes of shelf-derived materials to the central Arctic Ocean
- Simultaneous Separation of Actinium and Radium Isotopes from a Proton Irradiated Thorium Matrix
- Rapid desorption of radium isotopes from black shale during hydraulic fracturing / A model reconciling radium extraction with Marcellus wastewater production
- Targeted Alpha Therapy, an Emerging Class of Cancer Agents: A Review
- Pharmacodynamic study of radium-223 in men with bone metastatic castration resistant prostate cancer
- Accelerated burial of petroleum hydrocarbons in Arabian Gulf blue carbon repositories