Ir. Chemical button 18 mm.

<div>   </div> <div> <strong> Atomic number       <span class = "Apple-tab-span" style = "white-space: pre;"> </span>77</strong></div> <div> <strong> Atomic mass <span class = "Apple-tab-span" style = "white-space: pre;"> </span>       192,22 </strong> </div> <div> <strong> Density, kg / m? <span class = "Apple-tab-span" style = "white-space: pre;"> </ span >     22400 </strong> </div> <div> <strong> Temperature</strong></div> <div> <strong> melting, ° С <span class = "Apple-tab-span" style = " white-space: pre; "> </span>         2410 </strong> </div> <div>   </div> <div> Iridium is a very hard, refractory, silvery-white transition metal of the platinum group, which has a high density and is comparable in this parameter only with osmium. It has high corrosion resistance even at a temperature of 2000 ° C.   </div> <div> The element was discovered in 1804 by the English chemist S. Tennant (1761-1815) and named "Iridium" (from the Greek iris, genus iridos - rainbow) due to the varied colors of its salts. It is rarely found in the earth's crust, mainly as a satellite of platinum. & Nbsp; </div> <div>   </div> <p>   </p>