At the nano level, scientists often discover beautiful shapes and odd patterns. These are cadmium selenide nanocrystals that assembled themselves on top of a silicon wafer. The entire image, which was taken with a scanning electron microscope and had color added, is just 350 microns across - half the size of a period at the end of a sentence. Each hexagon is just 45 microns across. Cadmium selenide is an inorganic compound with the formula CdSe. Much of the current research on cadmium selenide is focused on its nanoparticles. A nanocrystal is a material particle having at least one dimension smaller than 100 nanometers (a nanoparticle) and composed of atoms in either a single-crystalline or poly-crystalline arrangement. Nanotechnology (nanotech) is the manipulation of matter on an atomic, molecular, and supramolecular scale.