# How to convert a hexagonal unit cell to rhombohedral unit cell?

Hexagonal unit cells can be converted to rhombohedral unit cells, and the latter unit cells have fewer atoms. But how can I convert them? Is there any software or codes that are able to do this transformation? For example, Cr2O3 has 30 atoms in the hexagonal unit cell, but can also be represented by 10 atoms in a rhombohedral unit cell.

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Oct 14 at 12:55

The VESTA package should be able to do it. But I'm not sure if it had rhombohedral or not. I recommend that you download and try Edit data -> Unit cell option. You should be able to find enough tutorials doing this. Alternatively, the Quantum ATK package can handle the job. Refer to the Tutorial.