Iridium- Element of the Week from 3/16 - 4/9

  

             Iridium is element number 77.  It is a hard, sliverish transition metal, which is related to platinum. Iridium is the second densest metal and the most corrosive resistant.

            The name of the element comes from the Latin word "iris," which means rainbow and who was the goddess of the rainbow. The name is appropriate because iridium salts are known for their bright colors.

            The British chemist Smithson Tennant discovered iridium and osmium at the same time in 1803. These elements were found in the leftover residue of dissolving platinum ore in an acid solution. Currently, platinum ores are still used to get iridium, and it can be found as a bi-product of mining nickel.

            Interestingly, there is a thin layer of iridium that spans across the entire world. Scientists believe that this is proof of a large meteor must have hit the Earth during (or at the end of, I guess) the Cretaceous period. Meteors and asteroids contain a higher amount of iridium than the crust of Earth.

            One of the largest uses of iridium is as an alloy with platinum. An alloy of 90% platinum and 10% iridium is actually the composition of the International Prototype Metre and kilogram mass. It is also used to make crucibles and other things that must undergo extreme temperatures.

            Iridium is used in particle physics for the production of antimatter, antiprotons in particular. Some other of the uses for iridium are less impressive. Iridium alloys are used in the tips of fountain pens, and an iridium pigment is used to paint porcelain an intense black color.