OneScience-Sugon/mp20

MP-20

Dataset Description

MP-20 is derived from the Materials Project database (Jain et al., 2013) and contains approximately 45,000 common inorganic materials. It covers most experimentally known materials with no more than 20 atoms in the unit cell. The data includes elemental compositions, CIF structures, space groups, formation energies per atom, DFT band gaps, bulk moduli, and magnetic densities.

Source paper: A. Jain et al., Commentary: The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1, 011002 (2013).
Paper: https://pubs.aip.org/aip/apm/article/1/1/011002/119685
DOI: https://doi.org/10.1063/1.4812323

This repository provides both raw CSV files and preprocessed caches. The data split contains 27,136 structures in the training set, 9,047 structures in the validation set, and 9,046 structures in the test set, for a total of 45,229 crystal structures.

The current data package contains 30 data files totaling approximately 83 MB.

Supported Tasks

This standardized data repository organizes the MP-20 training, validation, and test data for:

• Data analysis and statistics for inorganic crystal structures
• Training and evaluation of crystal structure generation tasks
• Conditional modeling of material properties
• Research on properties such as formation energy, band gap, bulk modulus, and magnetic density
• Crystal data loading, preprocessing, and data pipeline validation

Dataset Format and Structure

The data files are located in the data/MP20/ directory:

data/MP20/
├── raw/mp_20/
│   ├── train.csv
│   ├── val.csv
│   └── test.csv
└── cache/mp_20/
    ├── train/
    ├── val/
    └── test/

File Path	Format	Shape / Content	Description
raw/mp_20/train.csv	CSV + CIF	27,136 structures	Raw crystal and property data for the training set
raw/mp_20/val.csv	CSV + CIF	9,047 structures	Raw crystal and property data for the validation set
raw/mp_20/test.csv	CSV + CIF	9,046 structures	Raw crystal and property data for the test set
cache/mp_20/train/	NPY + JSON	27,136 structures	Preprocessed cache for the training set
cache/mp_20/val/	NPY + JSON	9,047 structures	Preprocessed cache for the validation set
cache/mp_20/test/	NPY + JSON	9,046 structures	Preprocessed cache for the test set
metadata/sha256_manifest.txt	SHA256	30 records	Data file integrity checksum manifest

CSV Data Format

Each row in a CSV file corresponds to one crystal structure. The cif field stores complete multiline CIF text, so the number of samples cannot be determined using a standard text line count.

Field	Type	Description
material_id	str	Materials Project structure ID
pretty_formula	str	Chemical formula
elements	list[str]	Set of elements in the structure
cif	str	Crystal structure in CIF format
spacegroup_number	int	Space group number
formation_energy_per_atom	float	Formation energy per atom
dft_band_gap	float	DFT band gap
dft_bulk_modulus	float / null	DFT bulk modulus; null for some samples
dft_mag_density	float	DFT magnetic density

Cache Data Format

Each train, val, and test cache directory contains the following files:

File	Type	Shape	Description
atomic_numbers.npy	int64	[N_atoms_total]	Atomic numbers concatenated across all structures
cell.npy	float64	[N_structures, 3, 3]	Unit-cell matrices
num_atoms.npy	int64	[N_structures]	Number of atoms in each structure
pos.npy	float64	[N_atoms_total, 3]	Fractional coordinates concatenated across all structures
structure_id.npy	str	[N_structures]	Structure IDs
formation_energy_per_atom.json	JSON	[N_structures]	Formation energy per atom property
dft_band_gap.json	JSON	[N_structures]	DFT band gap property
dft_bulk_modulus.json	JSON	[N_structures]	DFT bulk modulus property
dft_mag_density.json	JSON	[N_structures]	DFT magnetic density property

How to Use the Dataset

Download the dataset:

hf download --dataset OneScience-Sugon/mp20 --local-dir ./data

Validate the dataset directory, sample counts, array shapes, and SHA256 checksums:

python scripts/validate_mp20.py \
  --dataset-root data/MP20 \
  --checksum-manifest metadata/sha256_manifest.txt

Skip SHA256 verification and check only the data structure:

python scripts/validate_mp20.py \
  --dataset-root data/MP20 \
  --skip-checksum

Official OneScience Information

Platform	OneScience Main Repository	Skills Repository
Gitee	https://gitee.com/onescience-ai/onescience	https://gitee.com/onescience-ai/oneskills
GitHub	https://github.com/onescience-ai/OneScience	https://github.com/onescience-ai/oneskills

Limitations and License

This repository standardizes the directory structure of the MP-20 data and provides raw CSV files, preprocessed caches, a checksum manifest, and a validation script. It does not generate new samples or alter the original crystal structures or property data.

• The structures and properties in the data come from the Materials Project and the original MP-20 data curation pipeline. When using the data, cite the 2013 Materials Project paper by Jain et al. and the specific data version used.
• Some material properties contain missing values and must be filtered or masked as appropriate for the task.
• The Materials Project states that its data is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. This repository uses the same data license; appropriate attribution must be retained when using or redistributing the data.
• If individual entries contain third-party contributed data or additional restrictions, refer to the source of the corresponding entry and the information on its Materials Project page.