Datasets:

Scandium-Labs
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Scandium-Dataset

Scandium-Dataset provides a harmonized, quality-scored foundation of DFT-computed structural and thermodynamic properties across 267,230 materials from Materials Project, OQMD, and JARVIS-DFT. It supports the early screening stage of battery materials discovery — filtering by phase stability, electronic structure, and structural family — before downstream property prediction (ionic conductivity, mechanical stability, electrochemical window) via AIMD, NEB, or targeted DFT.

Previous versions positioned this as a solid-state battery discovery dataset. v1.0.0 corrects that framing: the data covers thermodynamic screening, not ionic transport. See CHANGELOG for details.

Version: v1.0.0
Total entries: 267,230 (Gold: 96,242 | Validated: 140,382 | Raw: 30,108 | Experimental: 498)
Strict Gold: 56,966 entries (subset of Gold with all gates passed)
Battery-relevant subset: 82,925 entries | Electrolyte candidate subset: 41,665 entries (strict Gold)

File names on disk (battery_candidate_subset_v1.json, solid_electrolyte_candidate_subset_v1.json) — the v3 suffix was retired in v1.0.0-rc2 when the scope was clarified.
Storage: Typed Parquet (dataset/entries_v4_typed.parquet, 47 columns) with indexed lookup — 178 MB with proper int/float/bool types for HF Dataset viewer compat.
Schema: Full column dictionary at SCHEMA.md — names, types, units, null semantics, source mappings.
Preview: dataset/entries_v4_typed_sample.parquet — 1,000-row stratified sample (1.25 MB) for schema inspection without downloading the full dataset.
Experimental data: 498 OBELiX entries integrated (Therrien et al. 2025) as experimental_gold tier with measured Li-ion conductivity.
Transport proxy draft: 24,873 BVSE migration barriers computed (bvlain engine) at 23% Li/Na coverage — see "Roadmap" below for the gap this addresses.

Quick Start

# Inspect schema (no download needed)
import pyarrow.parquet as pq
schema = pq.read_schema("dataset/entries_v4_typed_sample.parquet")
for f in schema:
    print(f"{f.name}: {f.type}")

# Load full dataset
import pandas as pd
df = pd.read_parquet("dataset/entries_v4_typed.parquet")
print(df.shape, list(df.columns))

# Stream in batches (low memory)
pf = pq.ParquetFile("dataset/entries_v4_typed.parquet")
for batch in pf.iter_batches(batch_size=1000, columns=["formula","band_gap"]):
    df_chunk = batch.to_pandas()
    print(f"Loaded {len(df_chunk)} rows")

# Filter by source before loading
df_mp = pd.read_parquet("dataset/entries_v4_typed.parquet", filters=[("source","=","mp")])

# Load partitioned source
df_mp2 = pd.read_parquet("dataset/partitioned/source=mp/data.parquet")

# Load from chunk
df_chunk = pd.read_parquet("dataset/chunks/entries_v4_chunk_00.parquet")

See SCHEMA.md for full column dictionary with units and null semantics.

Included vs. Not Included

Included	Not Included (requires augmentation)
Formation energy (eV/atom) — 100%	Ionic conductivity (S/cm)
Energy above hull (eV/atom) — 90.4%	Migration/activation energy (NEB)
Band gap (eV) — 99.9%	Electrochemical stability window
Space group, volume, density — 99.9%+	Elastic/shear moduli (full DFT)
Crystal structure (pymatgen `Structure` JSON) — 100%	Experimental validation beyond pilot OBELiX integration
Quality tier (Gold/Validated/Raw) — 100%
Provenance tracking (source, source_id, checksum) — 99.8%
SSE family classification (composition-based) — 100%
BVSE migration barrier proxy — 23% of Li/Na entries

Suitable For / Not Suitable For

Suitable for: phase stability screening, structural family classification, band gap prediction, materials-informatics benchmarking, pretraining general property predictors on inorganic crystal structures, cross-source DFT property harmonization studies.

Not suitable for (without augmentation): direct ionic conductivity prediction, SSE performance ranking, electrochemical stability assessment. The dataset contains migration barrier proxies for 23% of Li/Na entries, but at ~75% skip rate due to bond-valence parameter coverage, these do not constitute a complete transport-property layer.

What the Data Actually Supports

Property coverage (verified against Parquet store)

Property	Coverage	Notes
Formation energy	267,230 (100%)	From MP, OQMD, JARVIS-DFT
Energy above hull	257,799 (96.5%)	14,669 JARVIS entries newly computed in v1.0.0-rc2 via internal convex hull; 8,933 JARVIS entries lack EaH due to sparse chemical systems
Band gap	267,079 (99.9%)	151 OQMD entries with non-converged band gap
Space group	267,214 (100%)	spglib symmetry analysis
Volume	267,230 (100%)	From structure
Density	267,230 (100%)	From elements + volume
Structure JSON	267,230 (100%)	pymatgen Structure serialization
Quality score	267,230 (100%)	Composite score (0–88)
Provenance	267,230 (100%)	Source, source_id, checksum
Duplicate group	21,140 (7.9%)	Entries in dedup groups (31,997 total removed upstream)

SSE screening fields (stored in `ssb_screening` block)

Field	Coverage	Notes
SSE family	267,230 (100%)	Composition-based heuristic (not structure-based)
Mobile ion	267,230 (100%)	Li/Na/Mg presence-based
CAVD channel dimensionality	0%	Algorithm was not re-run against Parquet store
SSE candidate score	100%	5-gate system (thermo + electronic + mobility + window + mechanical)
Thermo stability flag	99.8%	E_hull < 0.025 eV/atom
Bulk/shear modulus	100%	Geometric density-based proxy (not DFT elastic tensors)
Stability window	1,814 (0.7%)	Grand-potential phase diagrams — computed for subset with low EaH
Interfacial reaction energy	39,706 (14.9%)	Decomposition energy vs Li
BVSE migration barrier	24,873 (23% of Li/Na)	bvlain v0.25.1, softBV percolation. 74.8% skip rate on attempted entries (98,773) due to bond-valence parameter coverage gaps

Sources

Source	Entries	License	Download Date
Materials Project	69,279	CC BY 4.0	2026-07-20
OQMD	171,780	Non-commercial + attribution	2026-07-20
JARVIS-DFT	25,673	CC0	2026-07-20
OBELiX (experimental)	498	Per-article terms	2026-07-24

License Warning

⚠️ This dataset is NOT uniformly licensed. Each entry carries its own license.

license: "CC-BY-4.0" → MP entries (commercial safe, 26.1%)
license: "CC0-1.0" → JARVIS entries (commercial safe, 9.6%)
license: "OQMD-noncommercial" → OQMD entries (non-commercial only, 64.3%)

See LICENSE_BREAKDOWN.md. A Commercial-Safe edition (MP+JARVIS, ~94,952 entries) is extractable via scripts/extract_commercial_safe_edition.py.

Tier System

Tier	Count	Criteria
Strict Gold ⭐	56,966	11 gates: base Gold + quality ≥ 80 + no defects + provenance
Gold	96,242	8 gates: validated + unique + stable + complete metadata
Validated	140,382	5 gates: valid structure + targets + no critical issues
Raw	30,108	Source + formula present (may have quality issues)
Experimental Gold	498	OBELiX entries with measured conductivity

Family Imbalance

The dataset skews heavily toward intermetallics (62.5%) and layered oxides (15.7%). Solid-electrolyte-relevant composition families are a small fraction:

Family	Total	Gold	Validated	Raw
Intermetallic	166,930	36,520	109,056	21,354
Layered oxide	42,015	26,295	12,756	2,964
Halide SSE	18,803	12,560	5,211	1,032
Sulfide SSE	16,359	9,458	5,591	1,310
NASICON	560	488	70	2
Garnet	23 + 113 experimental	19	4	0

If your target chemistry is garnets or sulfides specifically, usable Gold-tier entries number in the tens to low thousands — consider targeted acquisition (ICSD, structured literature extraction) before expecting ML models to generalize within these families.

BVSE Migration Barriers (Draft Quality)

Metric	Value
Total Li/Na entries	108,015
Excluded (>60 sites)	8,744
No structure (experimental)	498
Attempted	98,773
Barriers computed	24,873
Superionic (≤0.25 eV)	1,501
Good (0.25–0.40 eV)	4,705
Moderate (0.40–0.55 eV)	5,009
Poor (>0.55 eV)	13,658
Skipped (no BV params)	73,900
Errors	0
Coverage of attempted	25.2%
Coverage of all Li/Na	23.0%

Caveat: 73,900 skipped entries (~75% of attempted) reflect bond-valence parameter coverage, not a sampling gap. Entries are flagged with bvse_skip_reason. Engine: bvlain v0.25.1, validated against 7 known SSEs (5/7 pass within literature, 2 known-marginal outliers documented in KNOWN_ISSUES.md).

Roadmap to True SSE-Property Coverage

v1.0.0 provides thermodynamic and structural screening data. Planned extensions:

CAVD re-computation against the Parquet store (currently 0% coverage; algorithm exists in scripts/compute_cavd_channel_dimensionality.py)
JARVIS EaH re-computation against the Parquet store (currently 0% for 25,673 JARVIS entries; script exists in scripts/compute_jarvis_hull_energy.py)
BVSE barrier expansion — re-run with lower --max-sites threshold and extended parameter table to reduce the 75% skip rate
MLIP-NEB migration barriers for top-tier stable candidates (active development)
DFT NEB validation for a curated set of halide/sulfide/garnet candidates
Elastic tensor data from MP API for mechanical property validation (scaffold exists in scripts/compute_mechanical_properties.py)
Experimental conductivity cross-references beyond OBELiX pilot

Benchmark

Frozen train/val/test splits at dataset/splits/. Four split types with RF+Ridge baselines in MODEL_LEADERBOARD.md:

Split	Train	Val	Test	Purpose
Random 80/10/10	200,122	26,670	39,940	Basic generalization
Composition held-out	213,383	27,011	26,338	No formula overlap
Family held-out	260,984	5,165	583	Cross-family
Chemistry held-out	227,384	26,673	12,675	OOD (halides)

GNN baselines (CGCNN, MEGNet, ALIGNN) are in progress.

Intended Use

Primary: Upstream materials screening — filtering by phase stability, electronic structure, and structural family
Secondary: Cross-source DFT property harmonization, materials-informatics benchmarking, pretraining structure-based property predictors
Not recommended for: Quantitative phase diagram construction (use MP/OQMD directly), SSE conductivity ranking (requires transport-property labels not in this dataset)