Cif files are human-readible, hence we can look inside to see which information is stored there. Not only will this help you to understand how crystallographic information is supplied to a DFT codes, it will even allow you to write a cif file from scratch in case you need to do so.
The template for a cif file without any symmetry that is mentioned in the video, can be downloaded here (it’s called P1-empty.rtf for security reasons, save it as P1-empty.cif on your computer).
A few optional resources or tools related to cif files, that might come in handy:
Now you’re ready for this task:
I give you the name ‘litharge’. It’s the name of a crystal. Google for it’s chemical formula, then search the appropriate crystal in COD (or any other database you have access to). What’s its space group? What are the Wyckoff positions for all atoms? Show a picture of the unit cell, and indicate the coordinates of all atoms. Compare that with the coordinate list for the Wyckoff positions of that space group.
This task should demonstrate to you that you are able now to uncover a lot of information based on one single word (‘litharge’). You are able now to do this for every crystal with a name. If I give you ‘stephanite’, you can find its composition, space group, Wyckoff positions, cif file, picture of the unit cell,… And so on for every crystal with a common name (listed, for instance, here).
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, or if there is a concept from the video that you cannot apply to the cif file you found, 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 hereunder.