Number of atoms

Hi I am wondering if there is a way to pull the number of atoms used in an api search, which is listed on the summary page when I look up a specific material id on the website.

Hi @casfrueh,

Here is an example query to get you the number of sites and number of elements for silicon (mp-149).

from mp_api.client import MPRester

with MPRester("your_api_key") as mpr:
    docs =["mp-149"], fields=["material_id", "nsites", "nelements"]])

Does this answer your question?

– Jason

Hi Jason,

No this did not answer my question. I was able to pull nsites and elements already. But for mp-149 like in your example, the number of atoms listed on the website is 8. I was hoping to pull that when I pull the data for mp-149. But I can’t find the way to pull that info. It may not be possible. I was just wondering. Thanks for your help.

Best Regards,

That data is taken from the number of sites in the conventional unit cell. If you want that for a given MPID I would pull the structure, ensure it is the conventional cell setting, and then take len(structure) to get the number of sites.

– Jason