An affinity for astatine

Of all the elements in the periodic table, two have always struck me as alluringly mysterious: francium and astatine. There are more elusive elements than these, of course. But somehow superheavies like seaborgium and nihonium have come to seem almost familiar, for all that they have only ever existed as a handful of fleeting atoms: their ghostliness has always been a given. Francium and astatine, though, found their place at the bottom of their respective groups (until tennessine’s introduction to group 17 in 2010, that is) around 80 years ago: francium was discovered in 1939, astatine in 1940. The first of these was found by Marie Curie’s protégée Marguerite Perey, who was the first woman to be elected – shockingly, as recently as 1962 – to the French Académie des Sciences.

It’s probably, then, because we feel we should know them better by now that these elements seem so perplexing.