Can any one help me to calculate packing coefficient from crystal structure or from cif file?
Mr. Tarai,
``Crystal structure`` or ``cif''. The latter means Cristallographic Information File and contains information about the structure....Which program package you have available?
Use PLATON. It is available here:
http://www.cryst.chem.uu.nl/spek/platon/
Then do:
platon -o crystal.cif
Enter CALC VOID PROBE 1.2 GRID 0.2
The program will write out lots of info, including the packing coefficient.
I prefer to do this sort of calculation on paper or using Excel. Firstly calculate the cell volume, e.g. for a cube the cell volume = a x a x a. Next you need to calculate the volume your atoms are occupying within the cell;
You will know if your calculation is in the region of being correct if you're getting values somewhere between 0.5 to 0.75.
If the crystal structure consists of dissimilar atoms or ions with different radii, it is possible to obtain a more dense packing than 0.75 when you take into account the atoms of all varieties (small atoms fill the spaces between large atoms). At the same time the ratio of packaging that is relevant only to small atoms can be even less than 0.5.
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