Very. It appears in many glow-in-the-dark watches.
The first name was radium; some isotopes had in the past other names.
Radium is not a common commercial product.
Extremely expensive; radium is not a common commercial product. Radium can be delivered only to specialized research institutes.
Radium is not a common commercial product; radium (generally as radium chloride solution) is sold only to hospitals or specialized and controlled research laboratories.
Up to 700 0C radium is a solid metal.
Radium is not a common commercial product; radium is sold only to qualified and authorized research laboratories, generally in the form of radium chloride solutions or neutron sources Ra-Be.
Radium is not a common commercial product; radium is sold only to qualified and authorized research laboratories, generally in the form of radium chloride solutions or neutron sources Ra-Be.
Abundance of radium in the earth crust: 9.10-10 mg/kg Abundance of radium in the sea water: 8,9.10-14 mg/L
The atomic mass of the most common isotope of radium (226Ra) is: 226,025 409 8(25).
The density of radium at about room temperature is 5.5  g·cm−3. That's 5.5 grams per cubic centimeter, or 5.5 grams per milliliter. A link to the Wikipedia article on radium is provided.
radium
Radium is a chemical element, not a compound.