Usually, this strains the crystal lattice and increases the strength of a metal. Interstitial defects usually happen when a small atom fills the interstitial site of a larger atom’s crystal structure. There are many kinds of crystal defects (besides interstitial defects) such as grain boundaries, vacancies, and dislocations. When the interstitial site is not empty, it is considered an “interstitial defect.” Defects allow some of the most important material properties, such as ductility in metals. Depending on the number of atoms surrounding that empty space, the interstitial site can be designated as triangular (3), tetrahedral (4), octahedral (6), or cubic (8).Įach interstitial site is empty in a perfect crystal, but since these are the regions in the crystal with the most empty space, imperfect crystals have an occasional atom in these sites. Interstitial sites are empty spaces in a crystal lattice. If you have any pattern which doesn’t fill space completely (and we model atoms as spheres that can never fill space completely), you end up with gaps. Why are Interstitial Defects Important?Ĭheck out this article if you would like a basic introduction to crystallography, but the main fact you need to know is that crystals are any material made of atoms that repeat in a certain pattern.Thanks to Buttonwood for useful comments regarding graphical details and reminding about BFDH crystal morphology. on export you'll get something like this:Īlternatively, there is KrystalShaper (Windows only), a free lightweight program made specifically for displaying crystal morphologies: If you have CSD-Materials (paid option), then you'll be able to display BFDH theoretical crystal morphologies at once by going to CSD-Materials → Calculations → BFDH Morphology. → hkl and add the planes by Miller indices:

(This also automatically populates the list of planes with the planes denoting BFDH crystal morphology.) Alternatively, tweak the volume populated by the atoms if needed. Once the CIF is loaded, go to Calculate → Packing/Slicing. Open your CIF file by default Mercury loads an asymmetric unit. I used the structure of calcite from COD ( 1010962.cif). It also allows to add as many $(hkl)$ planes as you want. Mercury (available on Windows, Linux, MacOS) has a free version and is arguably the best crystallographic viewer for beginners.

Crystalmaker add atoms