Radium chloride radium chloride is weakly paramagnetic with a magnetic susceptibility of 1.05. It also differs from barium chloride by the flame color, which is red as opposed to green for barium chloride. Radium chloride is still used for the initial stages of the separation of radium from barium during the extraction of radium from pitchblende. The large quantities of material involved (tonnes of ore for milligrams of radium) favour this less costly (but less efficient) method over those based on radium bromide or radium chromate (used for the later stages of the separation). It was also used in medicine to produce
Radium ("ray"): this was in recognition of radium's power of emitting energy in the form of rays. On September 1910, Marie Curie and André-Louis Debierne announced that they had isolated radium as a pure metal through the electrolysis of a pure radium chloride (RaCl) solution using a mercury cathode, producing a radium–mercury amalgam. This amalgam was then heated in an atmosphere of hydrogen gas to remove the mercury, leaving pure radium metal. Later that same year, E. Eoler isolated radium by thermal decomposition of its azide, Ra(N). Radium metal was first industrially produced in the beginning of the 20th century by