How to distinguish experimental or theoretical structure entries


I would like to know whether the structure entries pulled from MP is from experimental work (like from ICSD), or from pure theoretical calculatioin.

I noticed that the reference (bibtex) attached to some entries do not have any experimental work paper reference, just Jain, A.'s Mateirals Project 2013 APL Materials paper. Can this be used as a standard way to distinguish?

Or maybe the mp- or mvc- id number? Though I think this just refers to materials project or multivalent cathode project.

Thank you!


Hi Long, welcome to the MP forums. I’m not sure if it’s perfectly suited for determining whether there’s an experiment associated with a material, but you can determine whether a given material on MP has an ICSD associated with it. On the web, you can determine whether material has an ICSD by looking at the bottom of the page in the ICSD field, for example the entry for nickel has several ICSD ids, whereas this Rb2ZrO3 doesn’t have any.

Using the API, you can similarly determine whether a material has any icsd IDs associated with it:

from pymatgen import MPRester
with MPRester() as mpr:
    mpr.query({"icsd_ids": {"$ne": []}})

This is basically querying the database for all of the materials which have a non-empty list in their icsd_ids field.

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Hi Joseph,

Thanks for your quick reply. If the entry doesn’t have ICSD associated, is it definitely not from experimental synthesis and structure characterization work?

I would say no, but it’s far more likely to be purely theoretical (or at least from preliminary theory work) in that case. For example, many of the non-icsd affiliated materials are from user submissions through the crystal toolkit (e. g. IrO3), and therefore might have some provenance from experiment that is not included in the submission.

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I see. So how about mvc- (multivalent cathode project) entries? Are they purely theoretical? I didn’t find associated icsd.

For example,

The mvc- entries should be assumed theoretical in general unless they have an associated experimental reference or database ID. These entries were enumerated originally in search of new multivalent battery cathode materials. Note also that the ICSD does include some theoretical structures – we are working on how to distinguish these entries. Also note that we have ingested for calculations many structures from the Pauling File database, which is for experimental structures. Materials matching Pauling File entries have IDs listed in the “pf_ids” fields, much like matching ICSD IDs are listed in the “icsd_ids” field as @Joseph_Montoya mentioned above.