Isotopes of tungsten

Naturally occurring tungsten (₇₄W) consists of five isotopes. Four are considered stable (W, W, W, and W) and one is slightly radioactive, W, with an extremely long half-life of (1.59±0.05)×10 years. This results in about two alpha decays of W per gram of natural tungsten per year, so for most practical purposes, W can be considered stable. The other naturally occurring isotopes are also capable of alpha decay and so only observationally stable.

Artificial radioisotopes of tungsten have been observed from W to W, the most stable of which are W with a half-life of 120.96 days, W with a half-life of 75.1 days, W with a half-life of 69.77 days and W with a half-life of 21.6 days. All of the remaining radioactive isotopes have half-lives less than one day, and most of these less than 8 minutes. The most stable known meta state is W with half-life 6.40 minutes.