Tungsten nuclides

The source preparation for tungsten Mossbauer spectroscopy is in general cumbersome, apart from the production of a, the parent nuclide of The first... 

Which of the following nuclides would you expect to be radioactive liNi, ifCu, Ag, tungsten-184, polonium-206 Justify your choices. 

Even though the Mossbauer effect has been observed for almost 50 different elements and ca. 100 different nuclides, only a few of these elements are widely used as Mossbauer effect probes. The nuclides which are both experimentally viable and yield useful chemical information are iron-57, tin-119, antimony-121, and europium-151. More difficult to use but of importance in coordination chemistry are gold-197, nickel-61, ruthenium-99, tellurium-125, iodine-129, dysprosium-161, tungsten-182, and neptunium-237. Among these isotopes, iron-57 is by far the easiest, most informative, and most widely used nuclide in both traditional coordination chemistry and in studies of biologically significant coordination complexes. 

---