Cadmium powder. Coloured scanning electron micrograph (SEM) of crystals of fine cadmium powder. Cadmium (atomic number 48; atomic mass 112. 40) is a soft silver-white metallic element (symbol Cd). Cadmium occurs naturally as sulphite or carbonate in zinc ores. It is often used in batteries, electroplating and in bearings with low coefficients of friction. Cadmium is also used in control rods of nuclear reactors, because of its high absorption of neutrons. It is a highly toxic metal that, because of industrial dumping, has become an environmental pollutant. Magnification: x295 at 6x7cm size.