Problem: As molten iron cools to 1674 K, it adopts one type of cubic unit cell; then, as the temperature drops below 1181 K, it changes to another, as depicted below:Which crystal structure has the greater packing efficiency?

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FREE Expert Solution

To solve this problem, we will need to calculate the packing efficiencies of both unit cells.

The first unit cell is a face-centered cubic unit cell as we see that there are 8 corner atoms and 6 face atoms.


Recall that packing efficiency is the percentage of occupied space in the unit cell.


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Problem Details

As molten iron cools to 1674 K, it adopts one type of cubic unit cell; then, as the temperature drops below 1181 K, it changes to another, as depicted below:

Which crystal structure has the greater packing efficiency?