Question: Why is Astatine so difficult to obtain and keep in laboratories?

Stuart Archer answered on 18 Jun 2013:

Good question! Astatine is radioactive which means that it changes into other elements whenever it gives off radiation, plus it’s very hazardous to work with. One of the main properties of a radioactive element is it’s ‘half-life’ – the time it takes for the amount of radioactivity from it to halve.

The problem with astatine is that it’s half life is short – it’s longest lived form has a half life of a little over 8 hours meaning that in two days over 98% of it has disappeared (assuming my maths is right…). Anything that’s radioactive generates heat – the more radioactive, the more heat it gives off. Astatine is so radioactive that if we could make a chunk of it big enough to be seen by the human eye it would immediately vapourise because of the heat it gives out!

Also, astatine is only formed by the radioactive decay of heavier elements such as radium or francium, so at any one time it’s believed that there is less than 30 grams of astatine naturally occuring in the Earth!