Chromium is a chemical element with the symbol Cr and atomic number 24. It is used in plating, which is a process of coating a metal surface with a thin layer of another metal to protect it from corrosion or to give it a decorative finish. Chromium is also found in its trivalent form, which is an oxidation state of 3. Trivalent chromium is used in many industrial processes, such as chrome plating, tanning, and dyeing.