To study whether in situ conversion proceeds in a way useful for CLEM, α-SeNPs were imaged by scanning electron microscopy (SEM). The locations of specific particle groups were noted (Figure ). High bin (2kx2k) images were collected at low magnification so that large areas of the grid could be viewed. Following this imaging, the nanoparticles were transformed to ZnSe metal selenide nanoparticles by incubating the grid with solution containing Zn 2+ . The grid was then imaged by SEM, examining the same areas of the grid imaged prior to ZnSe conversion. Figure , panel B shows a distribution of nanoparticles that appears essentially identical to the distribution prior to Zn 2+ incubation. The grid was also examined by TEM with SAED, collecting diffraction patterns from the particles observed in Figure , panel B. This data is shown in Figure , where the SAED pattern was indexed to the characteristic (111), ( ), ( ) and (511) planes of Zinc Blende phase of ZnSe.