Radium, Physical and Chemical Properties

Physical Properties

Radium is a radioactive alkaline-earth metal that is found in trace amounts in uranium and thorium ores. One gram uranium contains 0.33 × 10⁻⁶ g Ra. Uranium 235 is present to the extent of 0.7% in uranium ores; it was once called actino-uranium because it produced actinium, hence the actinium series. Radium and its salts exhibit luminescence and impart a carmine color to flame. Radium emits alpha, beta, and gamma rays and was once used for cancer treatment because of its gamma rays. It produces neutrons when mixed with beryllium. Its most stable isotope, Ra 226, has a half-life of 1,601 years. Radium 223 has a half-life of 11.43 days and that of Ra 224 is 3.363 days. All three isotopes decays into radon gas which then decays to polonium which is a solid product hence the danger of respiring radon – once it enters the lungs it will never leave and may cause lung cancer because of the bombardment of the tissue with alpha particles (Fig. 1). Radium loses about 1% of...