Platinum is a chemical element with symbol Pt and atomic number 78. It is dense, malleable, ductile, highly unreactive, precious, gray-white transition metal.
                                 
                                
                                    
                                    P 4716 (OTTO) Platinum foil, 0.1 mm, thick , 99.95% Cas 7440-06-4 - used in fuel cells as a catalyst for the reduction of oxygen.