09-10-2018, 03:01 PM
:tch-pyrite: The Structure of Diamond :tch-pyrite:
Diamond is most commonly known as the gemstone traditionally presented on a ring in a marriage proposal. However, it's not just used during engagements and actually has a number of different uses! Diamond is the hardest known material, allowing it to be used in cutting and drilling tools (in the form of polycrystalline diamond, or PCD). It is also very good at transferring heat, having the highest known thermal conductivity, and so may become useful in electronics. It can be doped with boron impurities to provide electrical conductivity, potentially offering applications in sensors. And that's only just scratching the surface!
Diamond is made entirely out of carbon (y'know, the stuff your pencil lead contains) and is a giant covalent structure - made up of covalent bonds between the atoms. In a covalent bond, electrons are shared between the atoms, allowing them to attain a full outer shell (their happy place ).
Graphite, which pencil lead is made out of, is also a giant covalent structure containing only carbon. So, what's the difference? Why is one a shiny gemstone with all these crazy good properties, and the other a black substance. Well, it's to do with the way the atoms are arranged. In diamond, all the bonds between the atoms are strong, and there is a regular arrangement. In graphite, there is some regular structure, but it is in layers, which are only held together by weak interactions. Effectively, we are comparing a 3D structure to a 2D structure. Thus, there is a huge difference in the eventual properties of the two materials. Diamond's hardness and high thermal conductivity arise from the fact that all the bonds involved are strong and short.
If anyone has any questions or comments about diamond, do fire away! I will probably update this soon with some more random facts about diamond. Thinking of doing how diamonds are made next, but we'll see!