I have a question regarding various planes in an FCC, and determine their packing fractions.(adsbygoogle = window.adsbygoogle || []).push({});

I searched but couldn't find anything :)

For example, one of the planes is the (100) plane, and I have said there are 2 full atoms (1 in the middle, and 4 quarters from each side), distance 'a' apart. Using the usual packing fraction equation ((Volume of atom x number of atoms)/Volume of cell), but replacing the volume with area, I calculate this to be pi/2, which is wrong because it can't be higher than one

My exact numbers were:

Area of a circle = pi x r², where r=a/2

-> (pi x a²/4) x 2 (-# of atoms) / a²

The a² cancels, as does the 4 with the 2 to leave pi over 2.

Any help would be appreciated, cheers :)

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# How to calculate 2D packing fractions?

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