The issues on retrieval of crystal properties based on Crystal System

[brl1999]

Hi everyone. I need some guidance on retrieving structural properties of materials, specifically the lattice parameters (a, b, and c lengths) and cell angles, constrained by the crystal system type (such as cubic). Could someone advise on how to perform this query using the new_api? Thank you!

[DanielYang59]

Hi @brl1999. If I understand correctly, you want to get materials via MP_API of specific crystal system (cubic in your case)? Checkout the official docs.

If that is the case you might want to try the following:

To get all matches:

from mp_api.client import MPRester
import pandas as pd


# Query MP data (e.g., for cubic crystal systems)
# Reference: https://api.materialsproject.org/docs#/
with MPRester() as mpr:
    cubic_materials = mpr.materials.summary.search(
        crystal_system="Cubic"
    )

    # Convert the query results to a list of dictionaries
    data = [material.model_dump() for material in cubic_materials]

# Convert to DataFrame
df_cubic = pd.DataFrame(data).set_index("material_id")

# Cache the DataFrame (this is ipynb magic, you would need ipynb instead of py)
%store df_cubic

# Load cache
# %store -r df_cubic

To inspect a specific materials with ID:

demo_struct = df_cubic.loc["mp-10018"]
print(demo_struct.structure)

# To get the Structure object itself (use under mpr context manager)
# mpr.get_structure_by_material_id("mp-10018")

Would give:

Full Formula (Ac1)
Reduced Formula: Ac
abc   :   4.027830   4.027829   4.027830
angles:  59.999995  60.000001  59.999995
pbc   :       True       True       True
Sites (1)
  #  SP      a    b    c    magmom
---  ----  ---  ---  ---  --------
  0  Ac     -0   -0    0        -0

[brl1999]

Thank you for your answering! However, I wonder if it's possible to directly acquire the batch abc-axis lengths and angles from the API using the material ID, while restricting the crystal system as you mentioned. Otherwise, I would need to download a large number of CIF files, which would take more time.

[DanielYang59]

I wonder if it's possible to directly acquire the batch abc-axis lengths and angles from the API using the material ID, while restricting the crystal system as you mentioned.

I'm afraid I don't really understand your use case. If you already have the MP ID, you could just mpr.get_structure_by_material_id("mp-10018").

Or if you don't have the MP ID and want to query them with specific constrain, you could use my previous code which takes around 20 s for 20k structures (might vary depending on your network condition).

I would need to download a large number of CIF files, which would take more time.

I don't think you would need to download the cif to get the info. May I know kind of latency/performance are you expecting? If you want super lower latency I believe building a local cache (usually 50 μs to 5 ms range for SSD/HDD) would be magnitudes faster than fetching remotely (~5 s for MP server)?

[brl1999]

Thank you again for your response! I believe my question has been solved.

[DanielYang59]

okay great to know, happy coding