# MgNi2: enthalpy of formation

> Enthalpy of formation of MgNi2: 13 literature value(s) with sources, pages and quotes and DFT values (Materials Project / OQMD), from ORCHID.

HTML: https://data.orchid-project.org/compounds/MgNi2.html · Markdown: https://data.orchid-project.org/compounds/MgNi2.md

13 accepted literature formation-enthalpy value(s) (experimental 10, model 3); experimental median -21.073 kJ/mol-atom (n = 5); Materials Project -21.279 kJ/mol-atom (mp-aaaaadyx); OQMD -22.517 kJ/mol-atom (oqmd-17634).

Systems: [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html)

## Literature values

Table: Enthalpy of formation of MgNi2 reported in the literature (13)

| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---:|---|---:|---|---|---|---|---|---|
| -77.87 kJ/mol (basis unstated) | MgNi2 | 298.15 | experimental |  | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [1] Jacobs 1998; _cites ref. 9_ | Table 4, p. 7, row 2; `ORC-RYAQ4LKL7J.2be89c` |  |
| -59.91 kJ/mol (basis unstated) | MgNi2 | 298.15 | experimental |  | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [1] Jacobs 1998; _cites ref. 12_ | Table 4, p. 7, row 6; `ORC-4RGH55XUQP.21ebbb` |  |
| -55.68 kJ/mol (basis unstated) ± 6.28 | MgNi2 | 298.15 | experimental |  | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [1] Jacobs 1998; _cites ref. 10_ | Table 4, p. 7, row 3; `ORC-WRHWA6GMI3.9bfa2d` |  |
| -55.27 kJ/mol (basis unstated) ± 2.1 | MgNi2 | 298.15 | experimental |  | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [1] Jacobs 1998; _cites ref. 11_ | Table 4, p. 7, row 5; `ORC-PMMJZUFYMJ.6995a1` |  |
| -53.22 kJ/mol (basis unstated) ± 10 | MgNi2 | 298.15 | experimental |  | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [1] Jacobs 1998; _cites ref. 16_ | Table 4, p. 7, row 7; `ORC-3IFUULPCB5.824c81` |  |
| -25.92 kJ/mol-atom | MgNi2 | 298.15 | experimental | Vap. press. | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [2] Islam 2005; _cites Schmahl 1958_ | Table 4, p. 7, row 4; `ORC-KARWEPEIDM.17caf0` |  |
| -21.47 kJ/mol-atom | MgNi2 | 298.15 | experimental | emf | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [2] Islam 2005; _cites Lukashenko 1966_ | Table 4, p. 7, row 3; `ORC-4ID3VNUSY5.355647` |  |
| -21.073 kJ/mol-atom | MgNi2 | 298.15 | experimental | Soln. calo. | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [2] Islam 2005; _cites Feufel 1995_ [doi](https://doi.org/10.1016/0925-8388%2895%2901526-4) | Table 4, p. 7, row 7; `ORC-QVTPLSNWR4.43109e` |  |
| -20.62 kJ/mol-atom | MgNi2 | 298.15 | experimental | Vap. press. | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [2] Islam 2005; _cites Smith 1960_ [doi](https://doi.org/10.1016/0001-6160%2860%2990188-7) | Table 4, p. 7, row 6; `ORC-ZUOAQ2M7RC.4ad923` |  |
| -19.23 kJ/mol-atom | MgNi2 | 298.15 | experimental | Soln. calo. | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [2] Islam 2005; _cites King 1964_ [doi](https://doi.org/10.1016/0001-6160%2864%2990056-2) | Table 4, p. 7, row 5; `ORC-5PCDUQPPMY.171a4e` |  |
| -55.65 kJ/mol (basis unstated) ± 4.61 | MgNi2 |  | model |  | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [1] Jacobs 1998 | Table 4, p. 7, row 4; `ORC-QRH66KL2K7.750685` |  |
| -48.086 kJ/mol (basis unstated) | MgNi2 |  | model |  | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [1] Jacobs 1998 | Table 4, p. 7, row 1; `ORC-GPOK2SAIGV.177028` |  |
| -21.55 kJ/mol-atom | MgNi2 |  | model | Cal. | [Mg–Ni](https://data.orchid-project.org/systems/MG-NI.html) | [2] Islam 2005 | Table 4, p. 7, row 2; `ORC-WEVCNGEEW4.265df8` |  |

### Uncertainty budget

Components kept separate, in the value's unit (literature [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md), [UNCERTAINTY_CALIBRATION.md](https://data.orchid-project.org/literature/UNCERTAINTY_CALIBRATION.md)): effective = max(sqrt(max(printed, reading, method)^2 + composition^2 + conversion^2), scatter). The method floor is the robust between-study scatter of the method class in ORCHID (calibrated) or a documented prior; printed values and printed uncertainties are unchanged.

Table: Uncertainty budget of the literature values of MgNi2

| Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective |
|---:|---|---:|---:|---|---:|---:|---:|---:|
| -77.87 | kJ/mol (basis unstated) |  | 0.005 | 10.5 (unknown, calibrated) |  |  |  | 10.5 |
| -59.91 | kJ/mol (basis unstated) |  | 0.005 | 10.5 (unknown, calibrated) |  |  |  | 10.5 |
| -55.68 | kJ/mol (basis unstated) | 6.28 | 0.005 | 10.5 (unknown, calibrated) |  |  |  | 10.5 |
| -55.27 | kJ/mol (basis unstated) | 2.1 | 0.005 | 10.5 (unknown, calibrated) |  |  |  | 10.5 |
| -53.22 | kJ/mol (basis unstated) | 10 | 0.005 | 10.5 (unknown, calibrated) |  |  |  | 10.5 |
| -25.92 | kJ/mol-atom |  | 0.005 | 4.2 (kems_vapour, calibrated) |  |  |  | 4.2 |
| -21.47 | kJ/mol-atom |  | 0.005 | 4.6 (emf, cleaned_below_threshold) |  |  |  | 4.6 |
| -21.073 | kJ/mol-atom |  | 5.000e-4 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -20.62 | kJ/mol-atom |  | 0.005 | 4.2 (kems_vapour, calibrated) |  |  |  | 4.2 |
| -19.23 | kJ/mol-atom |  | 0.005 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -55.65 | kJ/mol (basis unstated) | 4.61 | 0.005 | 11.7 (model_calculated, calibrated) |  |  |  | 11.7 |
| -48.086 | kJ/mol (basis unstated) |  | 5.000e-4 | 11.7 (model_calculated, calibrated) |  |  |  | 11.7 |
| -21.55 | kJ/mol-atom |  | 0.005 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |

## DFT formation energies

Lowest-energy entries at this composition. Materials Project and OQMD use different energy references and are never averaged. 1 eV/atom = 96.485 kJ/mol-atom.

Table: DFT formation energy of MgNi2

| Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical |
|---|---|---:|---:|---|---:|---:|---|
| Materials Project | mp-aaaaadyx | -21.279 | -0.220546 | P6_3/mmc | 0 | 0 | no |
| OQMD | oqmd-17634 | -22.517 | -0.233375 | P63/mmc | 0 | 0 | no |

DFT sources: A. Jain et al., Commentary: The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002. [doi:10.1063/1.4812323](https://doi.org/10.1063/1.4812323) (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501-1509; S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010. [doi:10.1007/s11837-013-0755-4](https://doi.org/10.1007/s11837-013-0755-4) (CC BY 4.0); 

## Sources

1. M.H.G. Jacobs, P.J. Spencer, A critical thermodynamic evaluation of the system MG-NI, Calphad 22, 513-525 (1998). [doi:10.1016/s0364-5916(99)00008-5](https://doi.org/10.1016/s0364-5916%2899%2900008-5)
2. F. Islam, M. Medraj, The phase equilibria in the Mg–Ni–Ca system, Calphad 29, 289-302 (2005). [doi:10.1016/j.calphad.2005.08.006](https://doi.org/10.1016/j.calphad.2005.08.006)

## 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-Parity: DFT-vs-experiment formation-enthalpy benchmark (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735943
- 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); 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; 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_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_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/).