Inconsistent results for mp-2176

When I query the mp-2176 structure via the python script from pymatgen.ext.matproj import MPRester I got a hexagonal structure with 6 atoms in it. However on the mp-2176 webpage, it is a cubic structure with 8 atoms in the cell. Does anyone know where the problem is?

Make sure to use the API key for our new API (see your dashboard) to retrieve the latest data shown on our website. You’ve probably set a legacy API key (see your legacy dashboard) and thus are retrieving legacy data.

Dear Patrick,

Thank you very much for your quick reply. I just confirmed with the new API from mp_api.client import MPRester with the new API key.

However, I still get the same wrong result. Plus, if I search mp-2176 in the webpage (Materials Project - Materials Explorer). I see the sites is also 6 instead of 8. Only if I get in the page of the material (mp-2176: ZnTe (Cubic, F-43m, 216)) I see the “correct” structure.

Interesting. Thanks for reporting this. @munrojm and I will take a closer look.

Dear Patrick,

Do we have update on this issue? I would like to update that I found another structure has a similar problem. mp-1067935 which shows 10 atoms in the website but 5 atoms in the query.

Best wishes,

Hey @Yi_Yao,

The website is showing the conventional unit cell by default for both the lattice parameters and the atomic positions. The problem is that even after selecting “primitive” under lattice, the atomic positions are not updated and keep showing the conventional unit cell. Perhaps this is something that should be fixed by the website admins.

Querying with MPRester() by default returns the primitive cell. Therein lies the difference that you see. If you’re using get_structure_by_material_id() method of MPRester(), you can pass conventional_unit_cell=True and you will see the same structure as you see on the website. If you query using the instead, you can do SpaceGroupAnalyzer(struct).get_conventional_standard_structure() to get the conventional unit cell.

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