# Mg2Si: enthalpy of formation

> Enthalpy of formation of Mg2Si: 32 literature value(s) with sources, pages and quotes and DFT values (Materials Project / OQMD), from ORCHID.

HTML: https://data.orchid-project.org/compounds/Mg2Si.html · Markdown: https://data.orchid-project.org/compounds/Mg2Si.md

32 accepted literature formation-enthalpy value(s) (experimental 18, model 7, DFT 5, unspecified 2); experimental median -26.15 kJ/mol-atom (n = 18); Materials Project -12.42 kJ/mol-atom (mp-aaaaacap); OQMD -15.603 kJ/mol-atom (oqmd-17649).

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

## Literature values

Table: Enthalpy of formation of Mg2Si reported in the literature (32)

| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---:|---|---:|---|---|---|---|---|---|
| -61.9 kJ/mol-atom | Mg2Si | 298.15 | experimental | Knusden cell | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1966Cau_ | Table 3, p. 3, row 6; `ORC-TVHTHUHXFG` |  |
| -29.7 kJ/mol-atom | Mg2Si | 298.15 | experimental | Calorimetry | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1971Bla_ | Table 3, p. 3, row 8; `ORC-E56JCQJWKX` |  |
| -27.9 kJ/mol-atom | Mg2Si | 298.15 | experimental | Knudsen cell | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1963Rya_ | Table 3, p. 3, row 3; `ORC-6WSWRP4O2O` |  |
| -27.1 kJ/mol-atom | Mg2Si | 298.15 | experimental | Calorimetry | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1967Ger_ | Table 3, p. 3, row 7; `ORC-NAZH3V3DPB.bd04ab` |  |
| -26.67 kJ/mol-atom | Mg2Si | 298.15 | experimental | emf | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Lukashenko 1964_ | Table 2, p. 4, row 4; `ORC-BQMOVUXMWI` |  |
| -26.4 kJ/mol-atom | Mg2Si | 298.15 | experimental | emf | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1964Luk_ | Table 3, p. 3, row 4; `ORC-FMNPCEPMA2.5cc81c` |  |
| -26.4 kJ/mol-atom | Mg2Si | 298.15 | experimental |  | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012; _cites Caulfield 1962_ | Table 3, p. 7, row 2; `ORC-NQ3FCXRLOR` |  |
| -26.37 kJ/mol-atom | Mg2Si | 298.15 | experimental | Calorimetry | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Caulfield 1962_ | Table 2, p. 4, row 3; `ORC-WGV2LZGFYW` |  |
| -26.3 kJ/mol-atom | Mg2Si | 298.15 | experimental | Calorimetry | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Kubaschewski 1949_ | Table 2, p. 4, row 1; `ORC-RRLRFVBSPR` |  |
| -26 kJ/mol-atom | Mg2Si | 298.15 | experimental |  | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012; _cites Kubaschewski 1949_ | Table 3, p. 7, row 1; `ORC-CR5XFWSRX4` |  |
| -25.9 kJ/mol-atom | Mg2Si | 298.15 | experimental | Calorimetry | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1949Kub_ | Table 3, p. 3, row 1; `ORC-K5PA43HKL6` |  |
| -22.99 kJ/mol-atom | Mg2Si | 298.15 | experimental | Vapor pressure | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Eldridge 1967_ | Table 2, p. 4, row 5; `ORC-IT4ZCWCHUS` |  |
| -22.2 kJ/mol-atom | Mg2Si | 298.15 | experimental | emf | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1981Rao_ | Table 3, p. 3, row 9; `ORC-PNANYQB5BW.8c73dd` |  |
| -22.16 kJ/mol-atom | Mg2Si | 298.15 | experimental | emf | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Rao 1981_ | Table 2, p. 4, row 6; `ORC-XT23ZMENP2` |  |
| -21.1 kJ/mol-atom | Mg2Si | 298.15 | experimental | Calorimetry | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Feufel 1997_ [doi](https://doi.org/10.1016/s0925-8388%2896%2902655-2) | Table 2, p. 4, row 7; `ORC-4NIT2EUNUZ` |  |
| -21.1 kJ/mol-atom | Mg2Si | 298.15 | experimental | Calorimetry | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1997Feu_ | Table 3, p. 3, row 10; `ORC-VU6QT2S3YK` |  |
| -14.21 kJ/mol-atom | Mg2Si | 298.15 | experimental | Vapor pressure | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Grjotheim 1962_ | Table 2, p. 4, row 2; `ORC-I7FSVUPWML` |  |
| -14.2 kJ/mol-atom | Mg2Si | 298.15 | experimental | VPTM | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 1962Grj_ | Table 3, p. 3, row 2; `ORC-QYTOKDYFUF.56456d` |  |
| -29.7 kJ/mol-atom | Mg2Si | 298.15 | model |  | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012; _cites Blachnik 1971_ | Table 3, p. 7, row 3; `ORC-TGU3PMLBRI` |  |
| -29.7 kJ/mol-atom | Mg2Si | 298.15 | model | Calculation | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Chakraborti 1992_ [doi](https://doi.org/10.1016/0364-5916%2892%2990041-u) | Table 2, p. 4, row 8; `ORC-YAOI6N6R5H` |  |
| -26.47 kJ/mol-atom | Mg2Si | 298.15 | model | Calculation | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Ludecke 1986_ | Table 2, p. 4, row 9; `ORC-N7FIHVHMXU` |  |
| -21.74 kJ/mol-atom | Mg2Si | 298.15 | model | Calculation | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Feufel 1997_ [doi](https://doi.org/10.1016/s0925-8388%2896%2902655-2) | Table 2, p. 4, row 11; `ORC-7UMSNJ5ULE` |  |
| -21.37 kJ/mol-atom | Mg2Si | 298.15 | model | Calculation | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000 | Table 2, p. 4, row 12; `ORC-4P7GS3EMYE` |  |
| -21.01 kJ/mol-atom | Mg2Si | 298.15 | model | Calculation | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [2] Yan 2000; _cites Lukas 1994_ | Table 2, p. 4, row 10; `ORC-XE6ZN6IYQS` |  |
| -21 kJ/mol-atom | Mg2Si |  | model | CALPHAD method | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009 | Table 3, p. 3, row 13; `ORC-VOMZWQPFCW.1cdbae` |  |
| -18.2 kJ/mol-atom | Mg2Si | 0 | DFT | First-principles | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009 | Table 3, p. 3, row 12; `ORC-5VIZ44FGIK` |  |
| -17.7 kJ/mol-atom | Mg2Si |  | DFT | First-principles | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [1] Yuan 2009; _cites ref. 2009Zha_ | Table 3, p. 3, row 11; `ORC-AP4XHDIAMA` |  |
| -17.7 kJ/mol-atom | Mg2Si | 298.15 | DFT | ab initio | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012; _cites Zhang 2009_ [doi](https://doi.org/10.1016/j.intermet.2009.03.017) | Table 3, p. 7, row 5; `ORC-FYZFTH4VM6` |  |
| -16.7 kJ/mol-atom | Mg2Si | 298.15 | DFT | ab initio | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012 | Table 3, p. 7, row 8; `ORC-3EP2RAVNHP.c91b91` |  |
| -15.4 kJ/mol-atom | Mg2Si | 298.15 | DFT | ab initio | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012 | Table 3, p. 7, row 9; `ORC-TKZQ4AI54G.9dc254` |  |
| -21.1 kJ/mol-atom | Mg2Si | 298.15 | unspecified |  | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012 | Table 3, p. 7, row 10; `ORC-OXJBML6GVQ.768fd4` |  |
| -21.1 kJ/mol-atom | Mg2Si | 298.15 | unspecified |  | [Mg–Si](https://data.orchid-project.org/systems/MG-SI.html) | [3] Schick 2012; _cites Feufel 1997_ [doi](https://doi.org/10.1016/s0925-8388%2896%2902655-2) | Table 3, p. 7, row 4; `ORC-QWF4L54JOC` |  |

### 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 Mg2Si

| Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective |
|---:|---|---:|---:|---|---:|---:|---:|---:|
| -61.9 | kJ/mol-atom |  | 0.05 | 4.2 (kems_vapour, calibrated) |  |  |  | 4.2 |
| -29.7 | kJ/mol-atom |  | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -27.9 | kJ/mol-atom |  | 0.05 | 4.2 (kems_vapour, calibrated) |  |  |  | 4.2 |
| -27.1 | kJ/mol-atom |  | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -26.67 | kJ/mol-atom |  | 0.001667 | 4.6 (emf, cleaned_below_threshold) |  |  |  | 4.6 |
| -26.4 | kJ/mol-atom |  | 0.05 | 4.6 (emf, cleaned_below_threshold) |  |  |  | 4.6 |
| -26.4 | kJ/mol-atom |  | 0.05 | 3.5 (unknown, calibrated) |  |  |  | 3.5 |
| -26.37 | kJ/mol-atom |  | 0.001667 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -26.3 | kJ/mol-atom |  | 0.01667 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -26 | kJ/mol-atom |  | 0.05 | 3.5 (unknown, calibrated) |  |  |  | 3.5 |
| -25.9 | kJ/mol-atom |  | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -22.99 | kJ/mol-atom |  | 0.001667 | 4.2 (kems_vapour, calibrated) |  |  |  | 4.2 |
| -22.2 | kJ/mol-atom |  | 0.05 | 4.6 (emf, cleaned_below_threshold) |  |  |  | 4.6 |
| -22.16 | kJ/mol-atom |  | 0.001667 | 4.6 (emf, cleaned_below_threshold) |  |  |  | 4.6 |
| -21.1 | kJ/mol-atom |  | 0.01667 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -21.1 | kJ/mol-atom |  | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) |  |  |  | 3.2 |
| -14.21 | kJ/mol-atom |  | 0.001667 | 4.2 (kems_vapour, calibrated) |  |  |  | 4.2 |
| -14.2 | kJ/mol-atom |  | 0.05 | 4.2 (kems_vapour, calibrated) |  |  |  | 4.2 |
| -29.7 | kJ/mol-atom |  | 0.05 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -29.7 | kJ/mol-atom |  | 0.01667 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -26.47 | kJ/mol-atom |  | 0.001667 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -21.74 | kJ/mol-atom |  | 0.001667 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -21.37 | kJ/mol-atom |  | 0.001667 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -21.01 | kJ/mol-atom |  | 0.001667 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -21 | kJ/mol-atom |  | 0.05 | 3.9 (model_calculated, calibrated) |  |  |  | 3.9 |
| -18.2 | kJ/mol-atom |  | 0.05 | 9.966 (dft, calibrated) |  |  |  | 9.966 |
| -17.7 | kJ/mol-atom |  | 0.05 | 9.966 (dft, calibrated) |  |  |  | 9.966 |
| -17.7 | kJ/mol-atom |  | 0.05 | 9.966 (dft, calibrated) |  |  |  | 9.966 |
| -16.7 | kJ/mol-atom |  | 0.05 | 9.966 (dft, calibrated) |  |  |  | 9.966 |
| -15.4 | kJ/mol-atom |  | 0.05 | 9.966 (dft, calibrated) |  |  |  | 9.966 |
| -21.1 | kJ/mol-atom |  | 0.05 | 3.5 (unknown, calibrated) |  |  |  | 3.5 |
| -21.1 | kJ/mol-atom |  | 0.05 | 3.5 (unknown, calibrated) |  |  |  | 3.5 |

## 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 Mg2Si

| Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical |
|---|---|---:|---:|---|---:|---:|---|
| Materials Project | mp-aaaaacap | -12.42 | -0.128725 | Fm-3m | 0 | 0 | no |
| OQMD | oqmd-17649 | -15.603 | -0.161717 | Fm-3m | 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. Xiaoming Yuan, Weihua Sun, Yong Du, Dongdong Zhao, Huaming Yang, Thermodynamic modeling of the Mg–Si system with the Kaptay equation for the excess Gibbs energy of the liquid phase, Calphad 33, 673-678 (2009). [doi:10.1016/j.calphad.2009.08.004](https://doi.org/10.1016/j.calphad.2009.08.004)
2. Xin-Yan Yan, Y. A. Chang, F. Zhang, A thermodynamic analysis of the Mg-Si system, JPE 21, 379-384 (2000). [doi:10.1361/105497100770339914](https://doi.org/10.1361/105497100770339914)
3. Michael Schick, Bengt Hallstedt, Albert Glensk, Blazej Grabowski, Tilmann Hickel, Milan Hampl et al., Combined ab initio, experimental, and CALPHAD approach for an improved thermodynamic evaluation of the Mg–Si system, Calphad 37, 77-86 (2012). [doi:10.1016/j.calphad.2012.02.001](https://doi.org/10.1016/j.calphad.2012.02.001)

## 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/).