Least-squares-fit overlays

7/7: Seventeen arsenic complexes

In this last example we'll look at an extreme case of seventeen molecules from a 2013 paper in Acta Cryst. section B. This particular structure solved easily using a P 1 triclinic unit cell with Z ' = 17. As explained in the paper, the structure is actually incommensurately modulated, but by all the usual metrics, the commensurate approximation refines about as well as the more rigorous treatment.

Here's what the asymmetric unit looks like:

The CIF, .xyz, and other files for this example are available here.

Individual .xyz files and the combined .rot may be obtained in the usual way using over-rip.py and over-rot.py. The latter giving the log file linked here. When the .rot file is processed by over-lay.py, the resulting 3D browser graphics look like this:

This last example was intended as a bit of fun and to show that there is no set limit to the number of structure models that can be overlayed with this method.

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