Big bang nucleosynthesis with bound states of long-lived charged particles

Charged particles ($X$) decaying after primordial nucleosynthesis are constrained by the requirement that their decay products should not change the light element abundances drastically. If the decaying particle is negatively charged ($X^{-}$) then it will bind to the nuclei. We consider the effects of the decay of $X$ when bound to Helium-4 and show that this will modify the Lithium abundances.