Chemistry - Does radioactivity affect chemical reactions?

Solution 1:

I'd like to add to the other answers. Although not directly an answer to your question, I do feel it's relevant. Radioactive decay can cause damage to crystalline solids.

Take the example of apatite $\left(\ce{Ca5[PO4]3[F,Cl,OH]}\right)$, which can host a bit of uranium in the crystal structure. When this uranium decays, the resulting particle damages the host crystal. The crystal can then be polished and etched to reveal these so called "fission tracks":

^{(source: Stanford Fission Track Thermochronology Laboratory)}

Heating of a damaged crystal will cause the damage to "heal" and the tracks to disappear. Thus, radioactive decay can indirectly induce chemical reactions. This routinely occurs in the deep Earth. It also has some very useful applications in geochronology, which you can read about in the Wikipedia article about fission tracks.

Solution 2:

During the nuclear reaction, the atomic number Z (and therefore chemical identity) changes (transmutation). In your example, $\ce{RaCl_2 -> \alpha^{2+} + RnCl_2^{2-} -> He + RnCl_2}$.

Radon being noble gas would react further, e.g. $\ce{RnCl_2 -> Rn + Cl_2}$

If the decaying atom would be a transition metal with ligands, it's properties should not change so drastically so that the ligands will stay attached.

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Solution 3:

I think we need to avoid concetrating too much on the atom at which the decay occured, it is true that many radioactive decays will cause bonds to break as a result of the recoil energy. But alpha, beta and gamma radiations coming from the radioactive atom can deposit energy in the solution, liquid, gas or solid where the radioactivity is present and thus cause chemical reactions to occur.

If you irradate water then the first products are the solvated electrons and H2O cations, these can then react to form a range of reactive species such as HO and H radicals. These can then react further to give things like hydrogen gas and hydrogen peroxide. All of these reactive species can cause chemical reactions to occur.

It is interesting that a solution of a radioactive chemical will undergo autoradiolysis which can change the chemical form of the radionuclide. For example if I was to start with a concentrated plutonium solution in the +6 oxidation state in an aqueous solution. Then if I was to seal it up then the radiation could cause the formation of other oxidation states of Pu, so I would soon end up with a mixture of Pu(III), Pu(IV), Pu(V) and Pu(VI). It is possible with additves to try to control the oxidation state of the plutonium (or other metal), so in some systems the chemistry can be tamed.