Materials Project ID Change and query


I have a question about the Materials Project ID’s. Were the MP ID’s recently modified a lot? I am using the data that I queried back in 2019 September or something, using the “get_entry_by_material_id” tag from the pymatgen MPRester. Now I cannot query quite a large fraction of the entries that I had previously. If I search them on the website, the pop up as a different MPID. I found that there was an update of MP Database on November of 2019. In this update, were some of the mpid’s deprecated?

If the original mpid points to a different mpid entry, what would be the difference between these two entries? Are all of the data except the ID (mpid) the same?

Would there be a way to use the “get_entry_by_material_id” to query the entries that pop up as different MPID?

The following MPID’s that have this issue are as follows:
mp-764149 --> mp-752568
mp-765099 --> mp-760182
mp-582900 --> mp-557652

Thank you!


Hi @KyuJung_Jun

There’s general confusion on what a material is. A Material is a collection of calculations, where each calculation has an ID of the form: mp-35434. Any of these IDs refer to that material. We have some rules on how we choose that material_id to make things a bit easier, but there are some instances where that material_id can change. One is when we deprecate calculations as we increase the standard for what goes into MP. The other is when we have found old calculations and need to put them back into the database. In both of these cases, the Material is still there.

We should definitely modify pymatgen to do this remapping for you.

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Hello @shyamd, is there a bit more information about these changes somewhere? I am trying to understand if I should be excluding the data I have that is associated with some retired mpids and it seems like from your description above, this kind of depends on the circumstance.

Thank you in advance for your help!