Radium

Category: alkaline earth metal Atomic number: 88 Colour: whiteish Melting point: 700°C (1,292°F) Boiling point: 1,737°C (3,159°F) First identified: 1898

When the Curies found polonium in pitchblende, they also found radium (which was named for its property of glowing in the dark). In 1911, Marie Curie went on to isolate the metal (with her colleague André Debierne) by electrolysing radium chloride with a mercury cathode.

The Radioactive Cookbook

It was very possibly radium that killed Marie Curie (she died of aplastic anaemia) – when she discovered radium, she used to enjoy going to the lab in the dark and watching the test-tubes glowing like fairy lights. The notebooks and papers she left behind still have to be kept in lead boxes and can only be viewed using radiation protection. Even the cookbook in her kitchen turned out to be extremely radioactive, presumably because she had handled it.

It occurs naturally in small quantities within uranium ores. A highly radioactive element, it has had some medical applications, notably in early cancer treatments, but these are mostly now redundant, although radium-223 is sometimes used to treat prostate cancer when it has spread to nearby bones.

Early in the twentieth century, radium was used in small quantities in luminous paints such as those used on clock dials. A famous court case of the 1920s involved the ‘radium girls’, five young women who had developed tumours after working in the US radium factory – they were using paint containing radium and were issued with no safety guidance. As well as handling the paint, some used to lick the tip of their paintbrushes into a point, thus ingesting small quantities of it. They won the case, but all died within a few years. Radium is no longer used in luminous paint, partly as a result of their courage in pursuing and winning that court case.