Its immediate decay product is the dense radioactive noble gas radon, which is responsible for much of the danger of environmental radium.

In the mid-1920s, a lawsuit was filed against the United States Radium Corporation by five dying "Radium Girl" dial painters who had painted radium-based luminous paint on the dials of watches and clocks.

The dial painters routinely licked their brushes to give them a fine point, thereby ingesting radium.

Currently, other than its use in nuclear medicine, radium has no commercial applications; formerly, it was used as a radioactive source for radioluminescent devices and also in radioactive quackery for its supposed curative powers.

Today, these former applications are no longer in vogue because radium's toxicity has since become known, and less dangerous isotopes are used instead in radioluminescent devices.

As the concentration of nitric acid increases, the solubility of radium nitrate decreases, an important property for the chemical purification of radium.).

With the exception of the carbonate, all of these are less soluble in water than the corresponding barium salts, but they are all isostructural to their barium counterparts.

Small amounts of barium impurities give the compound a rose color.

It is soluble in water, though less so than barium chloride, and its solubility decreases with increasing concentration of hydrochloric acid.

While studying the mineral earlier, the Curies removed uranium from it and found that the remaining material was still radioactive.