A structure written using the Structure.to method will write the data in P1 symmetry, even if the structure contains higher symmetry. As an example, if we create a diamond-ish structure
cube = Structure.from_spacegroup('Fd-3m',[(4,0,0),(0,4,0),(0,0,4)] , ['C',], [(0,0,0),])
and write it to a .cif file
the structure is recorded in P1 symmetry, even though the spacegroup is embedded in cube.
I see this has been brought up as an issue previously (issues:1230) and the explanation is that symmetry is computed on demand. Thus, the solution to recording the symmetrized data is to pass the keyword parameter symprec [float] (tolerance on adjacent atoms?) as a kwarg to the convenience method .to, as in
cube.to('cif', filename=join(base, 'diamond-ish.cif'), symprec=0.01)
which produces the expected behavior of a .cif file written in the appropriate spacegroup and asymmetric unit.
It seems like this is no longer a question, but since this wasn’t obvious to me when I started writing this comment, I’ll leave it here for posterity and to collect additional remarks on usage.