Debierne was principally a radiochemist; his first triumph came in 1900 with the discovery of a new radioactive element,
actinium
, which he isolated while working with pitchblende. In 1905 he went on to show that
actinium
, like
radium
, formed
helium
. This was of some significance in helping Ernest Rutherford to appreciate that some radioactive elements decay by emitting an alpha particle (or, as it turned out to be, the nucleus of a
helium
atom). In 1910, in collaboration with
Marie Curie
, he isolated pure metallic
radium
. |