Palladium is a shiny, silvery-white metal that resists corrosion.  It is one of the platinum group metals (PGMs), together with platinum, rhodium, ruthenium, iridium and osmium, but palladium has the lowest melting point and is the least dense of them.  In its applications it is most similar to platinum: useful in metallic form for the production of a variety of products and as a catalyst.    Palladium catalyzes reactions involved in petroleum cracking, water treatment, nitric acid production, and polymer manufacturing, and is found in catalytic converters and fuel cells as a catalyst.  Additionally, palladium is used to increase the rate of hydrogenation and dehydrogenation reactions, and serves many specialized catalytic functions in organic chemistry.    In fact, the 2010 Nobel Prize in Chemistry was given for the development of palladium-catalysed reactions used in organic synthesis.    As a metal, palladium is used in in electronics for plating of components, electrical contacts, and solder, and is also found in jewelry, watches, blood sugar test strips, and surgical instruments.    Alloyed with silver, palladium is used as electrodes in the production of multilayer ceramic capacitors.    Finally, a niche use of both platinum and palladium salts is in the production of fine-art black and white photographic prints with the platinotype process.