# GaN: enthalpy of formation > Enthalpy of formation of GaN: 8 literature value(s) with sources, pages and quotes and DFT values (Materials Project / OQMD), from ORCHID. HTML: https://data.orchid-project.org/compounds/GaN.html · Markdown: https://data.orchid-project.org/compounds/GaN.md 8 accepted literature formation-enthalpy value(s) (experimental 1, unspecified 7); experimental median -52.1 kJ/mol-atom (n = 1); Materials Project -63.373 kJ/mol-atom (mp-aaaaabey); OQMD -55.891 kJ/mol-atom (oqmd-6450). Systems: [Ga–N](https://data.orchid-project.org/systems/GA-N.html) ## Literature values Table: Enthalpy of formation of GaN reported in the literature (8) | Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote | |---:|---|---:|---|---|---|---|---|---| | -52.1 kJ/mol-atom ± 2 | GaN | 298.15 | experimental | Combustion calorimetry | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [1] Unland 2003; _cites Hahn 1940_ [doi](https://doi.org/10.1002/zaac.19402440203) | Table 2, p. 3, row 1; `ORC-L4ZDFWE5GW` | | | -157.7 kJ/mol (basis unstated) | GaN | 298.15 | unspecified | | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [2] Onderka 2002; _cites Madar 1975_ | Table AI, p. 18, row 25; `ORC-MK5TLO3SF5` | | | -157.7 kJ/mol (basis unstated) | GaN | 298.15 | unspecified | | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [2] Onderka 2002; _cites Karpinski 1984_ | Table AI, p. 18, row 26; `ORC-QQL76BGONT` | | | -156.8 kJ/mol (basis unstated) | GaN | 298.15 | unspecified | | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [2] Onderka 2002; _cites Ranade 2000_ | Table AI, p. 18, row 27; `ORC-PEOWFV2IWD` | | | -140.2 kJ/mol (basis unstated) | GaN | 298.15 | unspecified | | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [2] Onderka 2002; _cites MacChesney 1970_ | Table AI, p. 18, row 30; `ORC-LHYZF4HQHR` | | | -140 kJ/mol (basis unstated) | GaN | 298.15 | unspecified | | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [2] Onderka 2002; _cites Unland_ | Table AI, p. 18, row 17; `ORC-4T7BA2NHWJ.925d6c` | | | -117.1 kJ/mol (basis unstated) | GaN | 298.15 | unspecified | | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [2] Onderka 2002; _cites Davydov 1999_ | Table AI, p. 18, row 18; `ORC-XNAQL7HNT3.e3beeb` | | | -104.2 kJ/mol (basis unstated) | GaN | 298.15 | unspecified | | [Ga–N](https://data.orchid-project.org/systems/GA-N.html) | [2] Onderka 2002; _cites Hahn 1940_ | Table AI, p. 18, row 24; `ORC-LIAN2RVUAP` | | ### 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 GaN | Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective | |---:|---|---:|---:|---|---:|---:|---:|---:| | -52.1 | kJ/mol-atom | 2 | 0.025 | 1 (combustion_calorimetry, cleaned_below_threshold) | | | | 2 | | -157.7 | kJ/mol (basis unstated) | | 0.05 | 7 (unknown, calibrated) | | | | 7 | | -157.7 | kJ/mol (basis unstated) | | 0.05 | 7 (unknown, calibrated) | | | | 7 | | -156.8 | kJ/mol (basis unstated) | | 0.05 | 7 (unknown, calibrated) | | | | 7 | | -140.2 | kJ/mol (basis unstated) | | 0.05 | 7 (unknown, calibrated) | | | | 7 | | -140 | kJ/mol (basis unstated) | | 0.05 | 7 (unknown, calibrated) | | | | 7 | | -117.1 | kJ/mol (basis unstated) | | 0.05 | 7 (unknown, calibrated) | | | | 7 | | -104.2 | kJ/mol (basis unstated) | | 0.05 | 7 (unknown, calibrated) | | | | 7 | ## 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 GaN | Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical | |---|---|---:|---:|---|---:|---:|---| | Materials Project | mp-aaaaabey | -63.373 | -0.656817 | P6_3mc | 0 | 0 | no | | OQMD | oqmd-6450 | -55.891 | -0.57927 | P63mc | 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. J. Unland, B. Onderka, A. Davydov, R. Schmid-Fetzer, Thermodynamics and Phase Stability in the Ga–N System, Journal of Crystal Growth 256, 33-51 (2003). [doi:10.1016/s0022-0248(03)01352-6](https://doi.org/10.1016/s0022-0248%2803%2901352-6) 2. B. Onderka, J. Unland, R. Schmid-Fetzer, Thermodynamics and phase stability in the In–N system, J. Mater. Res. 17, 3065-3083 (2002). [doi:10.1557/jmr.2002.0445](https://doi.org/10.1557/jmr.2002.0445) ## 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=\, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).