Radium

In nature, radium is found in the Earth's crust, ~10⁻⁷ ppm, as a degradation product of uranium [4]. The isotopes found in nature are ²²³Ra (T_½ = 11.43 days), ²²⁴Ra (T_½ = 3.6319 days), ²²⁶Ra (T_½ = 1600 years) and ²²⁸Ra (T_½ = 5.75 years) [7].

In pure solid form, radium exist in a body-centered cubic structure [4]