docs/data_card.md

Data Card: Scandium Dataset v0.0

Dataset Description

• Name: Scandium Dataset v0.0
• Version: 0.0.0
• Date: 2026-07-21
• Publisher: Scandium Labs
• License: Multiple (CC BY 4.0 + CC0 + OQMD non-commercial)
• DOI: pending
• Repository: https://github.com/Scandium-Labs/Scandium-Dataset

Composition

• Total entries: 266,732
• Unique formulas: 148,141
• Sources: 3 (MP 69,279 + OQMD 171,780 + JARVIS 25,673)
• Material families: 10 (7 battery-relevant)
• Carrier elements: Li, Na, Mg, Ca, Zn, Al, K

Properties

Property	Unit	Coverage	Type
Formation Energy	eV/atom	100%	Continuous
Energy Above Hull	eV/atom	90.4%	Continuous
Band Gap	eV	99.9%	Continuous

Collection Methodology

All entries are sourced from established open DFT databases:

• Materials Project: PAW-PBE pseudopotentials, computed by MP consortium
• OQMD: PAW-PBE, computed by Wolverton group at Northwestern
• JARVIS-DFT: optPBE + TBmBJ band gaps, computed by NIST

Preprocessing

1. Unified schema: All sources mapped to common field names
2. Deduplication: 31,997 duplicates removed (chunked fingerprint matching)
3. Repair: 137,405 OQMD coordinate repairs, 171,764 space group computations
4. Quality scoring: 5 sub-scores (geometry, DFT, metadata, novelty, chemical)
5. Tiering: 3 tiers (Raw, Validated, Gold) + Strict Gold (11 gates)
6. Provenance: Checksums, repair history, dedup resolution per entry

Splits

Four frozen split types for benchmarking:

• Random 80/10/10
• Composition held-out (no formula overlap)
• Family held-out (smallest families as test)
• Chemistry held-out (halides as OOD test)

Quality Metrics

• Quality score range: 50-88 (0-100 scale, mean 77.4)
• Score calibration verified: monotonic relationship with label reliability
• Cross-source FE agreement: 0.20-0.23 eV/atom MAE
• Space group agreement (MP↔JARVIS): 78.6%

Intended Use

• Materials property prediction (FE, EaH, BG)
• Battery materials screening
• Representation learning pre-training
• Cross-source DFT comparison

Known Limitations

• No experimentally validated entries
• No ionic conductivity or migration barriers
• JARVIS entries lack EaH
• 16 OQMD entries missing space group
• Garnet family only 23 entries

Citation

@software{scandium_dataset_v3,
  title = {Scandium Dataset v0.0},
  version = {0.0.0},
  date = {2026-07-21},
  publisher = {Scandium Labs}
}