What Happens to Coordination Compounds When Radioisotopes Decay?

[Chemmjr18]

I was curious about the chemistry of radioisotopes. Specifically, when they form coordination compounds. What happens when they decay? I know a bit about tracer molecules, but what happens to the compound after it decays? Say a coordination compound containing a radioisotope as its center atom undergoes alpha decay. Does the coordination compound just collapse? Does it just adjust to fit the daughter nuclide? Any input is welcomed. Especially recommended literature.

 

[Borek]

In short: things get crazy and the result in pretty difficult to predict. Note that when the alpha particle is shot off the recoil shots the central atom in the opposite direction, breaking the molecule.

Sorry, no idea about the literature, but you can try to search in the Google Scholar.

 

[Chemmjr18]

In short: things get crazy and the result in pretty difficult to predict. Note that when the alpha particle is shot off the recoil shots the central atom in the opposite direction, breaking the molecule.

Sorry, no idea about the literature, but you can try to search in the Google Scholar.

Thanks! Will do.

 

[DrDu]

Perbromate was first synthesized by the radioactive decay of selenate:
https://en.wikipedia.org/wiki/Perbromate
So this is an example where the coordination structure remains stable upon decay.
The Mössbauer effect is used extensively to study the coordination of compounds. In the Mössbauer effect, the fact that the nuclear recoil is in some decay events taken up by the whole lattice is exploited. Hence the complex survives the emission of a gamma quantum.

 

[Borek]

So this is an example where the coordination structure remains stable upon decay.

Just to clarify: definitely there are cases where the atom stays in the position, especially during gamma and beta decay, where the mass of the emitted particle is quite low compared to nucleus. But the recoil is much stronger for alpha decay, which the OP has mentioned in the opening post (more or less the same can be said about neutron emission).

 

[DrDu]

Yes, Borek, I completely agree.
Let's try to estimate the recoil for different decay processes:
For the decay of Uranium 238, the energy carried away by the alpha particle is about E=4.27 MeV.
Assuming that the lions share of the energy is carried by the alpha particle, the momentum of the alpha particle is $P_\alpha=\sqrt{ 2M_\alpha E}=-P_\mathrm{Th}$ which has to be the negative of the momentum of the thorium nucleus formed. The energy of the latter is $E_\mathrm{Th}=P_\mathrm{Th}^2/2M_\mathrm{Th}$ or $E_\mathrm{Th}=M_\alpha/M_\mathrm{Th} E$, which is of the order of 10^5 eV and hence much larger than the binding energy of chemical compounds which is only some eV. So there is no chance for the molecule to survive the decay.
In beta decay, the energy E is typically smaller than 1 MeV, and the electron is about 8000 times lighter than the alpha particle. Furthermore, part of the momentum is carried away by the neutrino. Hence the recoil energy is smaller than 1eV and there is a good chance for the molecule to survive the decay.
In gamma decay, the recoil energy is even less so that the compound should almost always survive.