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ORCHID

Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

ORCHID logo: spinodal rose with an orchid at the stable centre

Open Repository for CALPHAD Hypotheses, Intelligence, and Discovery

ORCHID gathers openly available thermodynamic databases and the evidence behind them — assessed phase diagrams, invariant reactions, thermochemical measurements and first-principles energies — in one place, with the licence, source and evidence class of every value recorded. The data are versioned, citable and machine-readable, built to be used by people and by AI models alike.

2,912catalogued CALPHAD databases
2,788redistributable TDB files
3,828 / 3,916binary DFT hulls (Materials Project / OQMD)
2,695assessed CALPHAD hull documents (SGTE)
73,542literature values from 1,321 papers
10,430phases in the phase registry
23,129points in assessed phase diagrams
8,589ESPEI datasets: 6,453 from literature values and DFT, 2,136 optional phase constraints
9,570papers in the bibliography

Built on the SGTE collection

ORCHID would not have been possible without the enormous work of Bengt Hallstedt (RWTH Aachen University) and SGTE. The SGTE collection of binary datasets, gathered since the 1980s and made openly available in 2025, holds 2,773 datasets from 1,238 binary systems. ORCHID's calculated phase diagrams and much of its phase registry rest on it. Please cite B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, whenever you cite ORCHID, with its supplementary data, and the original assessment named in each file.

Explore

Literature data Version 1

Invariant reactions, transitions, phase compositions and thermochemical values from published papers, with evidence class, source, quote and page; also overlaid on the phase diagrams.

DFT vs experiment Version 1

Parity plots of literature formation enthalpies against Materials Project and OQMD, side by side, with error statistics and the quote behind every point.

Phase diagrams Version 1

Binary phase diagrams calculated from open TDB files, each linked to the exact file and checksum; compare assessments of the same system.

Compatibility network

All 2,912 databases as a network: which share identical pure-element descriptions and can be combined.

Database catalog

Search 2,912 databases by elements, category, licence and parser compatibility; download the redistributable files.

Binary hulls & mixing

DFT and CALPHAD formation-energy hulls and mixing curves on one composition axis, with every reference state named.

Mixing-energy explorer

Redlich–Kister mixing enthalpy, Gibbs energy and entropy for liquid, FCC, BCC and HCP across 2,552 binaries.

Model audit

Deterministic checks of 23,227 phases: temperature ranges, continuity, sublattice structure and interaction order.

CALPHAD practice guide

A reviewed bibliography of model-building practice: evidence, functions, sublattices, ordering, validation.

Data

DatasetContentsLicenceFiles
CatalogOne record per database: elements, phases, source, licence, distribution tierMIT (catalog)JSON · CSV
Bundled TDB files2,788 redistributable thermodynamic databases (SGTE binary supplement and others)Per source: CC BY 4.0, CC0, MIT, ODbL — see NOTICEdata/databases/
ORCHID-Hulls: DFT convex hullsBinary formation-energy hulls as interval documents; Materials Project v2026.04.13, OQMD v1.8CC BY 4.0 (upstream)dft-mp · dft-oqmd
ORCHID-Values: literature valuesValues from published papers with evidence class, conditions, citations/DOIs and the backing quote or table row (about)CC BY 4.0 (derived data); quotes are short excerpts under the publishers’ copyright, kept for verificationCSV.gz · JSONL.gz · per system
ORCHID-Hulls: CALPHAD hullsAssessed SGTE isotherms, same interval schemaCC BY 4.0calphad-sgte
ORCHID-Registry: phase registry10,430 phases of 1,241 binary systems: names across databases, papers and DFT, models, stability, structure when the stored evidence supports an assignment under the stated tier rules (browse)CC BY 4.0Parquet · JSON · schema
ORCHID-Assemblages: assessed phase assemblages23,129 (T, x, P) points inside the named phase fields of 2,178 expert-drawn binary diagrams (evidence class assessed_phase_diagram), with ESPEI ZPF datasetsCC BY 4.0Parquet · README
ORCHID ESPEI datasets8,589 ESPEI 0.9.1 datasets: 6,453 (12,513 values) from the literature values and DFT, with uncertainties and weights, and 2,136 optional phase-constraint datasets (16,538 points)CC BY 4.0index.csv · README
ORCHID-Bibliography9,570 papers ORCHID knows, with roles, evidence counts and 60,235 typed relations; DOIs checked against CrossrefCrossref metadata CC0; ORCHID fields CC BY 4.0browse · papers · edges

Releases

v2026.10 (Version 1, machine-extracted) is archived on Zenodo as eight citable datasets, each with its own DOI, linked by the umbrella record ORCHID data. Every value keeps its evidence class — experimental, model (linked to the exact TDB file by SHA-256), DFT or unspecified — and these are never mixed.

Release notes and known issues. What changed in each release is in the changelog; known issues and limits of Version 1 are listed in the dataset card (known limitations) and in each Zenodo record. Flags such as accepted and ESPEI-ready record screening results, not certification. Report an error: Contribute.

ORCHID-Values: literature values Version 1

Invariant reactions, transitions, phase compositions, thermochemical and structural values read from published papers, with quote and page. doi:10.5281/zenodo.23735569

ORCHID-Diagrams: calculated phase diagrams Version 1

pycalphad calculations from the SGTE binary collection, each tied to its TDB file by SHA-256. doi:10.5281/zenodo.23735859

ORCHID-Hulls: binary convex hulls Version 1

Materials Project, OQMD and assessed CALPHAD (SGTE) hulls as interval documents. doi:10.5281/zenodo.23735891

ORCHID-Parity: DFT vs experiment Version 1

Literature formation enthalpies against Materials Project and OQMD, with a Kim et al. 2017 cross-check. doi:10.5281/zenodo.23735943

ORCHID-Registry: phase registry Version 0

Every phase of each binary system: its names across databases, papers and DFT, models, stability and references; crystal structure only when the stored evidence supports an assignment under the stated tier rules. browse · doi:10.5281/zenodo.23735970

ORCHID-Assemblages: assessed phase assemblages Version 1

23,129 points deep inside the named phase fields of 2,178 expert-drawn binary diagrams from Okamoto's Desk Handbook, citing the original evaluations; ESPEI ZPF datasets. Data only; no page images. doi:10.5281/zenodo.23735996

ORCHID ESPEI datasets Version 1

8,589 ESPEI datasets: 6,453 from the literature values and DFT, one folder per evidence class, every value with its source DOI, uncertainty and weight, plus 2,136 optional, tagged phase-constraint datasets. files · doi:10.5281/zenodo.23735788

ORCHID-Bibliography Version 1

9,570 papers ORCHID knows: what was read, cited, assessed or discovered, with evidence counts and typed relations. browse · doi:10.5281/zenodo.23736021

Cite

Cite the dataset you use and the umbrella record, and the original source of every value (its paper and DOI).

Whenever you cite ORCHID, whether the paper, this website or any Zenodo DOI, please also cite B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833 (supplementary data). ORCHID would not exist without it.

Also cite the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file; A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0); G. Kim, S. V. Meschel, P. Nash, W. Chen, Experimental formation enthalpies for intermetallic phases and other inorganic compounds, Scientific Data 4 (2017) 170162, https://doi.org/10.1038/sdata.2017.162; for every diagram used, its original evaluation (citations[role=original_evaluation], DOI where matched) and H. Okamoto, Desk Handbook: Phase Diagrams for Binary Alloys, 2nd ed., ASM International (2010) as the compilation; the original source of every value you use (each dataset's `reference` / `bibtex`, references.bib; index.csv lists the DOIs); the papers themselves when you use their data (doi / citation of each bibliography record).

@misc{orchid_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@misc{orchid_dft_benchmark_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Parity: DFT-vs-experiment formation-enthalpy benchmark}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735943},
  url       = {https://doi.org/10.5281/zenodo.23735943},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_phase_registry_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Registry: phase registry of binary systems}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735970},
  url       = {https://doi.org/10.5281/zenodo.23735970},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_assessed_assemblages_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Assemblages: assessed phase assemblages of binary systems}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735996},
  url       = {https://doi.org/10.5281/zenodo.23735996},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_espei_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID ESPEI datasets: literature and database-derived thermodynamic fitting inputs}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735788},
  url       = {https://doi.org/10.5281/zenodo.23735788},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_bibliography_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Bibliography: papers and typed citation relations}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736021},
  url       = {https://doi.org/10.5281/zenodo.23736021},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}

For machines: llms.txt · CITATION.cff · Croissant metadata