Radon-219 is a radioactive isotope of the noble gas radon, which is part of the uranium decay series. It has a half-life of about 3.96 seconds, making it one of the shortest-lived isotopes of radon. Due to its rapid decay, it is not commonly found in significant amounts in nature. This isotope is produced from the decay of actinium-223, which itself is a decay product of uranium-235. Because of its short half-life, radon-219 does not accumulate in the environment and is primarily of interest in scientific research rather than in practical applications.