Lewis Acid

Wrought Iron is the purest form of iron. It contains 0.12 to 0.25% carbon and so it is the purest form of iron

Cesium

Catalytic converters are made from platinum or a similar, platinum-like metal, such as palladium or rhodium. A catalytic converter is an exhaust emission control device that reduces toxic gases and pollutants in exhaust gas from an internal combustion engine into less toxic pollutants by catalyzing a redox reaction (an oxidation or reduction reaction).