# Co–Mg system

> Co–Mg system: 11 accepted literature values (phase equilibrium 5, invariant reaction 5, formation 1) and 1 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/CO-MG.html · Markdown: https://data.orchid-project.org/systems/CO-MG.md

11 accepted literature values from 2 paper(s) (experimental 9, model 2); 1 calculated phase diagram(s). 7 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: [JSON](https://data.orchid-project.org/literature/systems/CO-MG.json) · [CSV](https://data.orchid-project.org/systems/CO-MG.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#CO-MG) · [interactive phase diagram](https://orchid-project.org/phase-diagrams/#CO-MG/CoMg-22Yan.json) · [phases (5)](https://data.orchid-project.org/phases/pages/CO-MG.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/CO-MG.html) · [Markdown](https://data.orchid-project.org/systems/CO-MG.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 9 |
| model | 2 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 5 |
| phase equilibrium | 5 |
| formation | 1 |

## Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Table: Assessments with a calculated phase diagram

| TDB file | Assessment | SHA-256 | Links |
|---|---|---|---|
| CoMg-22Yan.tdb | L.-F. Yang, X.-D. Si, H.-Q. Zhang, F.-Y. Gao, Y.-P. Zheng, Y.-L. Liu, Y.-R. Wang, Y. Du, J. Min. Metall. B, 58, 109-15(2022). [doi:10.2298/JMMB210606051Y](https://doi.org/10.2298/JMMB210606051Y) | `edaa24ff0861bcf5be4019caf839f602c299f43fa30a18bd3d37c0d0523c0974` | [viewer](https://orchid-project.org/phase-diagrams/#CO-MG/CoMg-22Yan.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/CoMg-22Yan.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/CoMg-22Yan.json) |

Table: Calculated three-phase invariants (model, mole fraction of the second component)

| TDB file | T (K) | Phases at the invariant |
|---|---:|---|
| CoMg-22Yan.tdb | 1242.77 | FCC_A1 (x(Mg) 0.00272) + CO2MG_C14 (x(Mg) 0.33333) + LIQUID (x(Mg) 0.72271) |
| CoMg-22Yan.tdb | 1242.77 | FCC_A1 (x(Mg) 0.00272) + CO2MG_C14 (x(Mg) 0.33333) + LIQUID (x(Mg) 0.7225) |
| CoMg-22Yan.tdb | 909.23 | CO2MG_C14 (x(Mg) 0.33333) + LIQUID (x(Mg) 0.98193) + HCP_A3 (x(Mg) 0.99928) |
| CoMg-22Yan.tdb | 909.23 | CO2MG_C14 (x(Mg) 0.33333) + LIQUID (x(Mg) 0.98198) + HCP_A3 (x(Mg) 0.99928) |
| CoMg-22Yan.tdb | 695.06 | FCC_A1 (x(Mg) 1.000e-5) + HCP_A3 (x(Mg) 2.000e-5) + CO2MG_C14 (x(Mg) 0.33333) |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/CO/CO-MG.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/CO/CO-MG.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the Co–Mg system (5)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 1243.15 | L + (αCo) -> MgCo2 | MgCo2: Mg 0.333333 | experimental | [1] Yang 2022; _cites Smith 1964_ | Table 3, p. 4, row 4; `ORC-SWT43UU252` |  |
| 1243.01 | L + (αCo) -> MgCo2 | MgCo2: Mg 0.333333 | model | [1] Yang 2022 | Table 3, p. 4, row 5; `ORC-5REBCU2LSR` |  |
| 908.15 | eutectic: L -> (Mg) + MgCo2 | MgCo2: Mg 0.333333 | experimental | [1] Yang 2022; _cites Wetherill 1935_ | Table 3, p. 4, row 1; `ORC-PL2SF63VRR` |  |
| 908.07 | eutectic: L -> (Mg) + MgCo2 | MgCo2: Mg 0.333333 | model | [1] Yang 2022 | Table 3, p. 4, row 3; `ORC-LDIA2CLRLN` |  |
| 906.15 | eutectic: L -> (Mg) + MgCo2 | MgCo2: Mg 0.333333 | experimental | [1] Yang 2022; _cites Cramer 1947_ | Table 3, p. 4, row 2; `ORC-XTCR3BDJJ5` |  |

## 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, Co–Mg system (1)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| MgCo2 | [Co2Mg](https://data.orchid-project.org/compounds/Co2Mg.html) | -8 kJ/mol-atom | 800 | experimental | -3.198 (mp-aaabxfmp) | -3.729 (oqmd-2066444) | [1] Yang 2022; _cites Hultgren 1973_ | p. 2; `ORC-GGHQW7AVAK` | “According to Hultgren et al. \[25\], the enthalpy of formation of MgCo2 was determined to be -8 kJ/mole·atoms at 800 K by vapor-pressure measurement.” |

## Other properties

### Phase equilibrium (5)

Table: Phase equilibrium, Co–Mg system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase composition |  | 911.35 | other; _liquid: Co 0.0165, Mg 0.9835_ | experimental | [2] Sheldon 1987; _cites ref. 35Wet_ | Table 1, p. 6, row 13; `ORC-5WR5FSJDYO` |  |
| Phase composition |  | 911.65 | other; _liquid: Co 0.0199, Mg 0.9801_ | experimental | [2] Sheldon 1987; _cites ref. 35Wet_ | Table 1, p. 6, row 14; `ORC-ZQ4EXQFLUD` |  |
| Phase composition |  | 916.95 | other; _liquid: Co 0.0077, Mg 0.9923_ | experimental | [2] Sheldon 1987; _cites ref. 35Wet_ | Table 1, p. 6, row 12; `ORC-GNWS2SQA5U` |  |
| Phase composition |  | 920.15 | other; _liquid: Co 0.0042, Mg 0.9958_ | experimental | [2] Sheldon 1987; _cites ref. 47Cra_ | Table 1, p. 6, row 15; `ORC-ID46JR6LTT` |  |
| Phase composition |  | 923.65 | other; _liquid: Co 0.0013, Mg 0.9987_ | experimental | [2] Sheldon 1987; _cites ref. 35Wet_ | Table 1, p. 6, row 11; `ORC-XZL3M2FI22` |  |

## Sources

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

1. L.-F. Yang, X-D. Si, H.-D. Zhang, F.-G. Gao, Y.-P. Zeng, Y.-L. Liu et al., Thermodynamic assessment of the Co-Mg binary system, J min metall B Metall 58, 109-115 (2022). [doi:10.2298/jmmb210606051y](https://doi.org/10.2298/jmmb210606051y)
2. R. I. Sheldon, E. M. Foltyn, D. E. Peterson, The Sn-U (Tin-Uranium) system, Bulletin of Alloy Phase Diagrams 8, 347-352 (1987). [doi:10.1007/bf02869271](https://doi.org/10.1007/bf02869271)

## 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-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). https://doi.org/10.5281/zenodo.23735859
- 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); 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).

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_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_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/).