Discovery of the astatine, radon, francium, and radium isotopes

Thirty-nine astatine, thirty-nine radon, thirty-five francium, and thirty-four radium isotopes have so far been observed; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented. (C) 2013 Elsevier Inc. All rights reserved.