The element osmium is the second densest metal and is twice as dense as lead. It was discovered along with its sister element iridium by Smithson Tennant in 1803 in the residue left after platinum ore was treated with aqua regia (a mixture of nitric and hydrochloric acids). Solid osmium is hard and brittle, has very low vapor pressure, and melts at very high temperatures. It is very difficult to fabricate and machine. Powdered osmium oxidizes in air to give off osmium tetroxide, which smells awful and is highly poisonous. Therefore, osmium is almost never used in its pure, unalloyed form. Instead, it is added to other platinum-group metals to make very hard alloys for fountain pen tips, phonograph needles, and electrical contacts where frictional wear must be minimized.
This online osmium sphere calculator helps you convert between different measuring units and is especially useful for professionals in the metals industry. It allows you to perform conversions between solid 1 centimeter in diameter osmium spheres and grams (g). It is also helpful for practicing density and other physical properties of the metal.
The reason why osmium is so much denser than gold, for example, is that the atoms have a smaller atomic radius and thus more mass can be packed into a given volume. In contrast, the atoms of gold have a bigger radius and require more space to pack the same amount of mass. Osmium and iridium also have very small electron orbitals, which further increases their density.