Hi James, --- Jen-Chang Chen wrote:

I'd like to apply cctbx as a generator of the crystallographic data. Based on the ICSD database, I can obtain a crystal structure of a mineral. Would it be possible to print out all atom positions in a unit cell or a supercell using cctbx?

The Cr2O3 example is included in the cctbx/cctbx/examples directory: http://phenix-online.org/cctbx_sources/cctbx/cctbx/examples/cr2o3_primitive_... Simply add this line to print out all atom positions in a unit cell: icsd_structure.expand_to_p1().show_summary().show_scatterers() For the supercell you have to figure out the change-of-basis matrix, then use the .change_basis() method of the xray.structure object. E.g. to double the length of the c-axis, add this at the end of the example script: from cctbx import sgtbx cb_op = sgtbx.change_of_basis_op("x,y,z*0.5") super_structure = icsd_structure.change_basis(cb_op=cb_op) super_structure.show_summary().show_scatterers() print Cheers, Ralf __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com