187Re
187Re, or rhenium-187, is a naturally occurring radioisotope of the transition metal rhenium (Re, atomic number 75). In nature, rhenium consists mainly of two isotopes, 185Re and 187Re, with 187Re accounting for about 62–63 percent of natural rhenium. 187Re is long-lived and decays by beta minus emission to 187Os (osmium-187). Its half-life is about 41.2 billion years, among the longest known for any radionuclide.
The 187Re–187Os decay system is used for geochronology. The ratio of 187Re to 187Os in sulfide minerals
Occurrence and production: Re occurs mainly in molybdenite and is refined as a by-product of molybdenum and
Safety and handling: As a long-lived radionuclide, 187Re is managed with standard radiological precautions in controlled