# B–Hf system

> B–Hf system: 57 accepted literature values (invariant reaction 32, formation 9, heat capacity / entropy / enthalpy 8, crystal structure 5) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/B-HF.html · Markdown: https://data.orchid-project.org/systems/B-HF.md

57 accepted literature values from 4 paper(s) (experimental 20, model 32, unspecified 5); 0 calculated phase diagram(s).

Data: [JSON](https://data.orchid-project.org/literature/systems/B-HF.json) · [CSV](https://data.orchid-project.org/systems/B-HF.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#B-HF) · [phases (9)](https://data.orchid-project.org/phases/pages/B-HF.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/B-HF.html) · [Markdown](https://data.orchid-project.org/systems/B-HF.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 20 |
| model | 32 |
| unspecified | 5 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 32 |
| phase transition | 3 |
| formation | 9 |
| heat capacity / entropy / enthalpy | 8 |
| crystal structure | 5 |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/B/B-HF.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/B/B-HF.json) · [CALPHAD hull HfB-10Kau](https://data.orchid-project.org/hulls/calphad-sgte/B/B-HF--HfB-10Kau.json) · [CALPHAD hull HfB-11Cac](https://data.orchid-project.org/hulls/calphad-sgte/B/B-HF--HfB-11Cac.json) · [CALPHAD hull HfB-97Bit-LB](https://data.orchid-project.org/hulls/calphad-sgte/B/B-HF--HfB-97Bit-LB.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the B–Hf system (32)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 3653 | congruent melting: L \<-> HfB2 | L: B 0.66; HfB2: B 0.66 | experimental | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 1, p. 2, row 1; `ORC-7F2EQJHEXL` |  |
| 3650 | congruent melting: B2Hf -> Liquid | B2Hf: B 0.666667, Hf 0.333333; Liquid: B 0.666667, Hf 0.333333 | model | [2] (ed.) 1998 | Table I, p. 138, row 5; `ORC-L3TKN6RNNE` |  |
| 3650 | congruent melting: L \<-> HfB2 | L: B 0.667; HfB2: B 0.667 | model | [1] Bittermann 1997 | Table 1, p. 2, row 3; `ORC-SGJYEKGFUL` |  |
| 3643 | congruent melting: L \<-> HfB2 | L: B 0.667; HfB2: B 0.667 | experimental | [1] Bittermann 1997; _cites ref. 71Por_ | Table 1, p. 2, row 2; `ORC-QVZSQEUV6B` |  |
| 2506 | congruent melting: L \<-> βHf | L: B 0; βHf: B 0 | model | [1] Bittermann 1997 | Table 1, p. 2, row 6; `ORC-ZKUKX6VZZR` |  |
| 2491 | congruent melting: L \<-> βHf | L: B 0; βHf: B 0 | experimental | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 1, p. 2, row 4; `ORC-AVPQZPV6YP` |  |
| 2473 | congruent melting: L \<-> βHf | L: B 0; βHf: B 0 | experimental | [1] Bittermann 1997; _cites ref. 71Por_ | Table 1, p. 2, row 5; `ORC-VS34Q3NV3O` |  |
| 2377.15 | peritectic: L + HfB2 -> HfB | L: B 0.219; HfB2: B 0.667; HfB: B 0.5 | model | [3] Cacciamani 2011 | Table 1, p. 4, row 2; `ORC-3U65PRSTNT` |  |
| 2377.15 | peritectic: L+HfB2=HfB | L: B 0.22; HfB2: B 0.666667; HfB: B 0.5 | model | [4] Pan 2021; _cites Bittermann 1997_ [doi](https://doi.org/10.1007/bf02646757) | Table 2, p. 5, row 3; `ORC-5QWLD35OJE` |  |
| 2377.1 | peritectic: Liquid + B2Hf -> + BHf | B2Hf: B 0.666667, Hf 0.333333; BHf: B 0.5, Hf 0.5 | model | [2] (ed.) 1998 | Table I, p. 138, row 2; `ORC-DTM45XSI5I` |  |
| 2377 | peritectic: L + HfB2 \<-> HfB | L: B 0.22; HfB2: B 0.667; HfB: B 0.5 | model | [1] Bittermann 1997 | Table 1, p. 2, row 8; `ORC-LIH57KNFPD` |  |
| 2373.15 | peritectic: L+HfB2=HfB | L: B 0.2213; HfB2: B 0.666667; HfB: B 0.5 | model | [4] Pan 2021 | Table 2, p. 5, row 4; `ORC-WTTMGUTM4U` |  |
| 2373 | peritectic: L + HfB2 \<-> HfB | L: B 0.24; HfB2: B 0.66; HfB: B 0.5 | experimental | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 1, p. 2, row 7; `ORC-AXBVQ63WOM` |  |
| 2343 | eutectic: L \<-> HfB2 + B | L: B 0.98; HfB2: B 0.667; B: B 1 | experimental | [1] Bittermann 1997; _cites ref. 71Por_ | Table 1, p. 2, row 13; `ORC-CHO2KFB4KX` |  |
| 2338.15 | eutectic: L=HfB2+(βB) | L: B 0.99; HfB2: B 0.666667; (βB): B 1 | model | [4] Pan 2021; _cites Bittermann 1997_ [doi](https://doi.org/10.1007/bf02646757) | Table 2, p. 5, row 5; `ORC-AEWSGTVLAS` |  |
| 2338.15 | eutectic: L -> HfB2 + B | L: B 0.99; HfB2: B 0.677; B: B 1 | model | [3] Cacciamani 2011 | Table 1, p. 4, row 3; `ORC-RRZR4AC3BS` |  |
| 2338 | eutectic: L \<-> HfB2 + B | L: B 0.99; HfB2: B 0.66; B: B 1 | experimental | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 1, p. 2, row 12; `ORC-CWKOUVBGEU` |  |
| 2338 | eutectic: L \<-> HfB2 + B | L: B 0.99; HfB2: B 0.667; B: B 1 | model | [1] Bittermann 1997 | Table 1, p. 2, row 14; `ORC-QDQOTWEDNY` |  |
| 2337.9 | eutectic: Liquid -> β-rhombo-B + B2Hf | B2Hf: B 0.666667, Hf 0.333333 | model | [2] (ed.) 1998 | Table I, p. 138, row 1; `ORC-U2OHHPYUM6` |  |
| 2337.15 | eutectic: L=HfB2+(βB) | L: B 0.9895; HfB2: B 0.666667; (βB): B 1 | model | [4] Pan 2021 | Table 2, p. 5, row 6; `ORC-U7K55VZRI7` |  |
| 2154.15 | eutectic: L -> HfB + bcc-Hf | L: B 0.15; HfB: B 0.5; bcc-Hf: B 0.01 | model | [3] Cacciamani 2011 | Table 1, p. 4, row 4; `ORC-MM53UIYS3F` |  |
| 2154.15 | eutectic: L=(βHf)+HfB | L: B 0.15; HfB: B 0.5 | model | [4] Pan 2021; _cites Bittermann 1997_ [doi](https://doi.org/10.1007/bf02646757) | Table 2, p. 5, row 7; `ORC-XCBUU7SESR` |  |
| 2154 | eutectic: L \<-> βHf + HfB | L: B 0.15; βHf: B 0.01; HfB: B 0.5 | model | [1] Bittermann 1997 | Table 1, p. 2, row 16; `ORC-NUDWTLMC2A` |  |
| 2153.6 | eutectic: Liquid -> BHf + bcc-A2 | BHf: B 0.5, Hf 0.5 | model | [2] (ed.) 1998 | Table I, p. 138, row 3; `ORC-HUZ6OWE5G7` |  |
| 2153 | eutectic: L \<-> βHf + HfB | L: B 0.13; HfB: B 0.5 | experimental | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 1, p. 2, row 15; `ORC-GE6CQM4M7L` |  |
| 2148.15 | eutectic: L=(βHf)+HfB | L: B 0.1515; HfB: B 0.5 | model | [4] Pan 2021 | Table 2, p. 5, row 8; `ORC-TPDFVBND75` |  |
| 2073 | peritectoid: βHf + HfB \<-> αHf | HfB: B 0.5 | experimental | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 1, p. 2, row 17; `ORC-AVAQTR7P3R` |  |
| 2066.15 | peritectoid: (βHf)+HfB=(αHf) | HfB: B 0.5 | model | [4] Pan 2021 | Table 2, p. 5, row 10; `ORC-3TIUBGMFZW` |  |
| 2064.15 | peritectoid: (βHf)+HfB=(αHf) | HfB: B 0.5 | model | [4] Pan 2021; _cites Bittermann 1997_ [doi](https://doi.org/10.1007/bf02646757) | Table 2, p. 5, row 9; `ORC-WIA33M5QXW` |  |
| 2064 | peritectoid: βHf + HfB \<-> αHf | βHf: B 0.007; HfB: B 0.5; αHf: B 0.015 | model | [1] Bittermann 1997 | Table 1, p. 2, row 18; `ORC-4EFVGD6FF6` |  |
| 2063.8 | peritectic: bcc-A2 + BHf -> hcp-A3 | BHf: B 0.5, Hf 0.5 | model | [2] (ed.) 1998 | Table I, p. 138, row 4; `ORC-VYVNFCAIJI` |  |
| 2063.15 | peritectoid: HfB + bcc-Hf -> hcp-Hf | HfB: B 0.5; bcc-Hf: B 0.007; hcp-Hf: B 0.015 | model | [3] Cacciamani 2011 | Table 1, p. 4, row 5; `ORC-JNDP3T7RHW` |  |

## Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from [dft_parity.json](https://data.orchid-project.org/literature/dft_parity.json).

Table: Enthalpies of formation, B–Hf system (9)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| HfB | [HfB](https://data.orchid-project.org/compounds/HfB.html) | -98.95 kJ/mol-atom ± 6.3 | 298.15 | experimental | -39.896 (mp-aaaaaanh) | -40.239 (oqmd-13677) | [1] Bittermann 1997; _cites ref. 64_ | Table 3, p. 4, row 21; `ORC-JDJTGHPS4K` |  |
| HfB | [HfB](https://data.orchid-project.org/compounds/HfB.html) | -79.905 kJ/mol-atom |  | model | -39.896 (mp-aaaaaanh) | -40.239 (oqmd-13677) | [1] Bittermann 1997 | Table 3, p. 4, row 22; `ORC-27USVZHC55.dd8998` |  |
| HfB2 | [HfB2](https://data.orchid-project.org/compounds/HfB2.html) | -117.633 kJ/mol-atom | 298.15 | experimental | -98.211 (mp-aaaaacys) | -98.749 (oqmd-5848) | [1] Bittermann 1997; _cites Krupka 1962_ | Table 3, p. 4, row 13; `ORC-FADPQLHUF3` |  |
| HfB2 | [HfB2](https://data.orchid-project.org/compounds/HfB2.html) | -109.633 kJ/mol-atom ± 2.93333 | 298.15 | experimental | -98.211 (mp-aaaaacys) | -98.749 (oqmd-5848) | [1] Bittermann 1997; _cites ref. 67Joh_ | Table 3, p. 4, row 15; `ORC-3TNKPI5YQB` |  |
| HfB2 | [HfB2](https://data.orchid-project.org/compounds/HfB2.html) | -106.567 kJ/mol-atom | 298.15 | experimental | -98.211 (mp-aaaaacys) | -98.749 (oqmd-5848) | [1] Bittermann 1997; _cites ref. 64_ | Table 3, p. 4, row 14; `ORC-2GT3C3X6RR` |  |
| HfB2 | [HfB2](https://data.orchid-project.org/compounds/HfB2.html) | -106.567 kJ/mol-atom |  | model | -98.211 (mp-aaaaacys) | -98.749 (oqmd-5848) | [1] Bittermann 1997 | Table 3, p. 4, row 20; `ORC-Q4AADJ4HWS.16a4bc` |  |
| HfB2 | [HfB2](https://data.orchid-project.org/compounds/HfB2.html) | -105.033 kJ/mol-atom | 298.15 | experimental | -98.211 (mp-aaaaacys) | -98.749 (oqmd-5848) | [1] Bittermann 1997; _cites Paderno 1959_ | Table 3, p. 4, row 12; `ORC-HF5NC5ZLMW` |  |
| HfB2 | [HfB2](https://data.orchid-project.org/compounds/HfB2.html) | -87.3 kJ/mol-atom ± 1.66667 | 298.15 | experimental | -98.211 (mp-aaaaacys) | -98.749 (oqmd-5848) | [1] Bittermann 1997; _cites Maslov 1978_ | Table 3, p. 4, row 17; `ORC-BN32W6A2PJ` |  |
| HfB2 | [HfB2](https://data.orchid-project.org/compounds/HfB2.html) | -83.1333 kJ/mol-atom ± 1.96667 | 298.15 | experimental | -98.211 (mp-aaaaacys) | -98.749 (oqmd-5848) | [1] Bittermann 1997; _cites Kitpichev 1979_ | Table 3, p. 4, row 18; `ORC-JH2JYKWPWY` |  |

## Other properties

### Phase transition (3)

Table: Phase transition, B–Hf system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase transition | 3650.15 K | 3650.15 | congruent melting: L=HfB2; _L: B 0.667; HfB2: B 0.666667_ | model | [4] Pan 2021; _cites Bittermann 1997_ [doi](https://doi.org/10.1007/bf02646757) | Table 2, p. 5, row 1; `ORC-BLYL2UGOO2` |  |
| Phase transition | 3651.15 K | 3651.15 | congruent melting: L -> HfB2; _L: B 0.667; HfB2: B 0.667_ | model | [3] Cacciamani 2011 | Table 1, p. 4, row 1; `ORC-RNBTF5GV6G` |  |
| Phase transition | 3651.15 K | 3651.15 | congruent melting: L=HfB2; _L: B 0.6666; HfB2: B 0.666667_ | model | [4] Pan 2021 | Table 2, p. 5, row 2; `ORC-GVTE5ENZY6` |  |

### Heat capacity / entropy / enthalpy (8)

Table: Heat capacity / entropy / enthalpy, B–Hf system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Entropy; _printed: S0_ | 22.235 J/mol-atom/K |  | HfB; _alloy: Hf 0.5_ | model | [1] Bittermann 1997 | Table 3, p. 4, row 22; `ORC-27USVZHC55.2f4fb9` |  |
| Entropy; _printed: S0_ | 14.3667 J/mol-atom/K ± 0.133333 |  | HfB2; _alloy: Hf 0.333333_ | experimental | [1] Bittermann 1997; _cites ref. 89Bol_ | Table 3, p. 4, row 19; `ORC-JMERQDLV4S.100fe1` |  |
| Entropy; _printed: S0_ | 14.2967 J/mol-atom/K |  | HfB2; _alloy: Hf 0.333333_ | model | [1] Bittermann 1997 | Table 3, p. 4, row 20; `ORC-Q4AADJ4HWS.bd8efe` |  |
| Entropy; _printed: S0_ | 14.2967 J/mol-atom/K |  | HfB2; _alloy: Hf 0.333333_ | experimental | [1] Bittermann 1997; _cites Westrum 1977_ [doi](https://doi.org/10.1016/0021-9614%2877%2990048-9) | Table 3, p. 4, row 16; `ORC-WPRAM3S7DW.bd216a` |  |
| Heat capacity; _printed: Cp0_ | 18.385 J/mol-atom/K |  | HfB; _alloy: Hf 0.5_ | model | [1] Bittermann 1997 | Table 3, p. 4, row 22; `ORC-27USVZHC55.e1e7ad` |  |
| Heat capacity; _printed: Cp0_ | 16.49 J/mol-atom/K |  | HfB2; _alloy: Hf 0.333333_ | experimental | [1] Bittermann 1997; _cites ref. 89Bol_ | Table 3, p. 4, row 19; `ORC-JMERQDLV4S.2d454a` |  |
| Heat capacity; _printed: Cp0_ | 16.6033 J/mol-atom/K |  | HfB2; _alloy: Hf 0.333333_ | model | [1] Bittermann 1997 | Table 3, p. 4, row 20; `ORC-Q4AADJ4HWS.010e8d` |  |
| Heat capacity; _printed: Cp0_ | 16.5967 J/mol-atom/K |  | HfB2; _alloy: Hf 0.333333_ | experimental | [1] Bittermann 1997; _cites Westrum 1977_ [doi](https://doi.org/10.1016/0021-9614%2877%2990048-9) | Table 3, p. 4, row 16; `ORC-WPRAM3S7DW.806079` |  |

### Crystal structure (5)

Table: Crystal structure, B–Hf system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Lattice a | 0.65185 not_printed | 298.15 | HfB; _alloy: Hf 0.5_ | unspecified | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 2, p. 3, row 6; `ORC-5YKTFXXROQ.9647f9` |  |
| Lattice a | 0.31438 not_printed ± 2.000e-5 | 298.15 | HfB2; _alloy: Hf 0.333333_ | unspecified | [1] Bittermann 1997; _cites ref. 85Vil_ | Table 2, p. 3, row 7; `ORC-PO4IYYQFNM.08f409` |  |
| Lattice b | 0.3216 not_printed | 298.15 | HfB; _alloy: Hf 0.5_ | unspecified | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 2, p. 3, row 6; `ORC-5YKTFXXROQ.aa82ba` |  |
| Lattice c | 0.492 not_printed | 298.15 | HfB; _alloy: Hf 0.5_ | unspecified | [1] Bittermann 1997; _cites ref. 65Rud1_ | Table 2, p. 3, row 6; `ORC-5YKTFXXROQ.46e44f` |  |
| Lattice c | 0.34793 not_printed ± 2.000e-5 | 298.15 | HfB2; _alloy: Hf 0.333333_ | unspecified | [1] Bittermann 1997; _cites ref. 85Vil_ | Table 2, p. 3, row 7; `ORC-PO4IYYQFNM.4e9056` |  |

## Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

1. H. Bittermann, P. Rogl, Critical assessment and thermodynamic calculation of the ternary system boron-hafnium-titanium (B-Hf-Ti), JPE 18, 24-47 (1997). [doi:10.1007/bf02646757](https://doi.org/10.1007/bf02646757)
2. I. Ansara, A. T. Dinsdale, M. H. Rand (eds.), COST 507: Thermochemical database for light metal alloys, Volume 2, EUR 18499 EN, Office for Official Publications of the European Communities, Luxembourg (1998), ISBN 92-828-3902-8.
3. G. Cacciamani, P. Riani, F. Valenza, Equilibrium between MB2 (M=Ti,Zr,Hf) UHTC and Ni: A thermodynamic database for the B–Hf–Ni–Ti–Zr system, Calphad 35, 601-619 (2011). [doi:10.1016/j.calphad.2011.10.003](https://doi.org/10.1016/j.calphad.2011.10.003)
4. Yafei Pan, Lei Huang, Jiuxing Zhang, Yong Du, Fenghua Luo, Shuyan Zhang, Thermodynamic Assessment of the Ternary B-Hf-Zr System with Refined B-Hf Description, J. Phase Equilib. Diffus. 42, 864-878 (2021). [doi:10.1007/s11669-021-00928-3](https://doi.org/10.1007/s11669-021-00928-3)

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735569
- R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). https://doi.org/10.5281/zenodo.23735891
- R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23736065

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); 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); 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.

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.

```bibtex
@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_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_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}
}
```

---

Derived data CC BY 4.0 ([licence](https://creativecommons.org/licenses/by/4.0/)): cite ORCHID ([CITATION.cff](https://data.orchid-project.org/CITATION.cff)) and the original sources. Quotes are short excerpts kept so that each value can be checked; they remain under the publishers' copyright and are not relicensed. Source papers, page images and full text are not redistributed. Field reference: [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt). Found an error? The report link of a value (Markdown: its id, ORC-..., in the Location column) opens a pre-filled GitHub issue, https://github.com/orchid-calphad/orchid-data/issues/new?template=report-value-error.yml&record_id=\<id>, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).