Chart of nuclides (IMAGE) Washington University in St. Louis Caption Chart of nuclides showing the isotopes Robert J. Charity and Lee G. Sobotka discovered in green (stable isotopes are indicated by black squares, and the proton drip line is shown in blue). The new fluorine isotope, <sup>13</sup>F, is the most removed from the drip line. Credit Image courtesy of Robert J. Charity, Washington University in St. Louis Usage Restrictions For editorial purposes License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.