Palladium

Palladium is a soft, silvery-white transition metal with atomic number 46 and symbol Pd. It is valued for catalytic activity, ability to absorb hydrogen, and resistance to corrosion.

Automotive catalytic converter: An exhaust-treatment device that uses catalysts to convert harmful gases into less harmful substances. Palladium helps catalyze the oxidation of hydrocarbons and carbon monoxide in many gasoline-vehicle converters.
Heterogeneous catalysis: Catalysis in which the catalyst and reactants occupy different phases, commonly a solid catalyst with gaseous or liquid reactants. Palladium surfaces accelerate reactions in exhaust treatment and industrial chemistry.
Periodic table: A tabular arrangement of chemical elements ordered by atomic number and recurring chemical properties. Palladium’s position in period 5 and group 10 links it to neighboring transition metals.
William Hyde Wollaston: An English chemist and physicist who discovered palladium and rhodium in the early nineteenth century. Wollaston isolated palladium from crude platinum ore and announced it in 1803.
Palladium market: The global trade in palladium, shaped by mining supply, recycling, industrial demand, and investment. Automotive catalyst demand and concentrated mine production can drive sharp price changes.
Palladium-catalyzed coupling reactions: Organic reactions that use palladium catalysts to form carbon–carbon or carbon–heteroatom bonds. These reactions exploit palladium’s ability to join molecular fragments efficiently.
Hydrogen absorption in metals: The uptake of hydrogen atoms into a metal’s structure, sometimes forming a solid solution or hydride. Palladium can absorb substantial hydrogen within its crystal lattice.
Transition metal: An element whose atom has a partially filled d subshell or forms cations with one. Palladium’s d-electron structure gives it the characteristic chemistry of a transition metal.
Discovery of palladium: The identification and isolation of palladium by William Hyde Wollaston in 1803–1804. Its discovery established palladium as a distinct element separated from platinum ores.
Platinum substitution in catalytic converters: The replacement of palladium with platinum in vehicle exhaust catalysts to manage cost, supply, or performance. High palladium prices have encouraged automakers to reformulate some catalysts with platinum.

Linked from 13 pages