Mechanistically, the reaction may proceed by Se disproportionation into Se 2+ and Se 2-. α-Se is composed of 8-membered Se rings (Se8 0 ) and polymeric Se chains (Sen 0 ) in a quasi-equilibrium of one and two electron propagation causing breakage and reformation of Se-Se bonds. The instability of α-Se results in the eventual rearrangement of the amorphous allotrope to the t-Se crystalline phase. To this extent, we hypothesized that it is possible to post-synthetically modify α-SeNPs by forming either a metal selenide (MSe) shell or particle using metals that tend to crystallize with Se through a disproportionation-type reaction. The proposed formation of MSe may occur as shown below: