 Rhenium has one stable isotope , rhenium @-@ 185 , which nevertheless occurs in minority abundance , a situation found only in two other elements ( indium and tellurium ) . Naturally occurring rhenium is only 37 @.@ 4 % <unk> , and 62 @.@ 6 % 187Re , which is unstable but has a very long half @-@ life ( ≈ 1010 years ) . This lifetime can be greatly affected by the charge state of rhenium atom . The beta decay of 187Re is used for rhenium @-@ osmium dating of ores . The available energy for this beta decay ( 2 @.@ 6 keV ) is one of the lowest known among all radionuclides . The isotope rhenium @-@ <unk> is notable as being one of the longest lived metastable isotopes with a half @-@ life of around 200 @,@ 000 years . There are twenty @-@ five other recognized radioactive isotopes of rhenium . 
