In this video, you’ll learn how to visualize a cif file that is not in a database, how to measure distances between atoms (and possibly much more), and how to transform a cif file without symmetry information into one that knows about the space group and Wyckoff positions. There are no slides for this video.
The procedure with FINDSYM and cif2cell as described in the video hereabove works in that way only for sufficiently symmetric space groups. If the symmetry is lower, an extra step is required (you will be made aware of this by an error message of cif2cell). This document explains you how to do that.
The litharge crystal you examined in the previous task is sufficiently simple to allow you to create its cif file without symmetry. Do that. Visualize that cif file, and measure the distances between two nearest oxygen atoms, and between the nearest O-Pb pair. Then use the procedure described in the video to create a cif file with symmetry information. Compare this to the cif file you found earlier in the database.
Continue with the cif file with symmetry information. Select a coordinate with a degree of freedom, and change the free number(s) drastically (multiply by 2). Draw a picture of the original and the new unit cell and observe visually what has happened. Pick any symmetry operation of the original cell, and convince yourself that it has not been broken by changing that free coordinate.
You don’t need to report on this task as long as everything goes well. But if you meet a problem that you cannot solve, then please describe it in the forum hereunder. If a problem appeared that you could solve, and about which you think your solution might help others, then please report about it in the forum below.