What is Iridium atom?

 

  Iridium is a chemical element with the symbol Ir and atomic number 77.  A very hard, brittle, silvery-white transition metal of the platinum group, iridium is considered to be the second-densest metal with a density of 22.56 g/cm3 as defined by experimental X-ray crystallography.  However, at room temperature and standard atmospheric pressure, iridium has been calculated to have a density of 22.65 g/cm3,0.04 g/cm3 higher than osmium measured the same way.  

     Still, the experimental X-ray crystallography value is considered to be the most accurate, and as such iridium is considered to be the second densest element.  It is the temperatures as high as 2000 C.  Although only certain molten salts and halogens are iridium dust is much more reactive and can be flammable.  

     Iridium was discovered in 1803 among insoluble impurities in natural platinum.  Smithson Tennant, the perimary discoverer, named iridium after the Greek goddess Iris, personification of the rainbow, because of the striking and diverse colors of its salts.  Iridium is one of the rarest elements in Earth's crust,  with annual production and consumption of only three tonnes.  197Ir and 193Ir are the only tow naturally occurring isotopes on iridium, as well as the only stable isotopes; the latter is the more abundant.