# H–Mg system > H–Mg system: 18 accepted literature values (invariant reaction 11, mixing / partial 7) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote. HTML: https://data.orchid-project.org/systems/H-MG.html · Markdown: https://data.orchid-project.org/systems/H-MG.md 18 accepted literature values from 1 paper(s) (experimental 14, model 4); 0 calculated phase diagram(s). 13 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/H-MG.json) · [CSV](https://data.orchid-project.org/systems/H-MG.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#H-MG) · [phases (6)](https://data.orchid-project.org/phases/pages/H-MG.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/H-MG.html) · [Markdown](https://data.orchid-project.org/systems/H-MG.md) Table: Accepted values by evidence class | Evidence class | Values | |---|---:| | experimental | 14 | | model | 4 | Table: Accepted values by property group | Property group | Values | |---|---:| | invariant reaction | 11 | | mixing / partial | 7 | Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/H/H-MG.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/H/H-MG.json) · [CALPHAD hull MgH-99Zen](https://data.orchid-project.org/hulls/calphad-sgte/H/H-MG--MgH-99Zen.json) ## Invariant reactions (literature) Table: Invariant reactions reported in the literature for the H–Mg system (11) | T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote | |---:|---|---|---|---|---|---| | 922.8 | L \<-> (Mg)+gas | (Mg): H 7.200e-4 | model | [1] Zeng 1999 | Table 5, p. 9, row 1; `ORC-EEFMEHG2CD` | | | 922.6 | L \<-> (Mg)+gas | (Mg): H 6.400e-4 | experimental | [1] Zeng 1999; _cites ref. 7_ | Table 5, p. 9, row 2; `ORC-OXR24U3IMP` | | | 834 | (Mg)+gas \<-> MgH2 | (Mg): H 0.093; MgH2: H 0.666667 | experimental | [1] Zeng 1999; _cites ref. 10_ | Table 5, p. 9, row 11; `ORC-LXVYHSSKWY` | | | 832 | (Mg)+gas \<-> MgH2 | (Mg): H 0.00806; MgH2: H 0.666667 | model | [1] Zeng 1999 | Table 5, p. 9, row 10; `ORC-GEVPSFODYL` | | | 700 | (Mg)+gas \<-> MgH2 | (Mg): H 0.00169; MgH2: H 0.666667 | model | [1] Zeng 1999 | Table 5, p. 9, row 8; `ORC-ESTW6OWQLS` | | | 700 | (Mg)+gas \<-> MgH2 | MgH2: H 0.666667 | experimental | [1] Zeng 1999; _cites ref. 10_ | Table 5, p. 9, row 9; `ORC-KICF2LSGB5` | | | 590 | (Mg)+gas \<-> MgH2 | MgH2: H 0.666667 | experimental | [1] Zeng 1999; _cites ref. 29_ | Table 5, p. 9, row 5; `ORC-CWZ4KJT65X` | | | 575 | (Mg)+gas \<-> MgH2 | MgH2: H 0.666667 | experimental | [1] Zeng 1999; _cites ref. 21_ | Table 5, p. 9, row 6; `ORC-TYGI4A3PCZ` | | | 573 | (Mg)+gas \<-> MgH2 | MgH2: H 0.666667 | experimental | [1] Zeng 1999; _cites ref. 19_ | Table 5, p. 9, row 7; `ORC-EVS53OYXVC` | | | 561 | (Mg)+gas \<-> MgH2 | (Mg): H 1.900e-4; MgH2: H 0.666667 | experimental | [1] Zeng 1999; _cites ref. 7_ | Table 5, p. 9, row 4; `ORC-VEEYJ2R4WP` | | | 560.7 | (Mg)+gas \<-> MgH2 | (Mg): H 1.600e-4; MgH2: H 0.666667 | model | [1] Zeng 1999 | Table 5, p. 9, row 3; `ORC-CHYYLHWP3V` | | ## Other properties ### Mixing / partial (7) Table: Mixing / partial, H–Mg system | Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote | |---|---:|---:|---|---|---|---|---| | Partial enthalpy; _printed: ΔH°_ | 21.06 kJ/mol-H | 668 | cph | experimental | [1] Zeng 1999; _cites ref. 24_ | Table 0, p. 4, row 1; `ORC-EW7X3N2QKY` | | | Partial enthalpy; _printed: ΔH°_ | 58 unknown ± 5 | 723 | cph | experimental | [1] Zeng 1999; _cites ref. 20_ | Table 0, p. 4, row 4; `ORC-PNUQJYIKWA` | | | Partial enthalpy; _printed: ΔH°_ | 51.76 unknown ± 16.63 | 773 | cph | experimental | [1] Zeng 1999; _cites ref. 10_ | Table 0, p. 4, row 5; `ORC-UZGUZEDWQT` | | | Partial enthalpy; _printed: ΔH°_ | 24.4 unknown ± 1.2 | 776 | cph | experimental | [1] Zeng 1999; _cites ref. 25_ | Table 0, p. 4, row 3; `ORC-LGKEV2ZCOJ` | | | Partial enthalpy; _printed: ΔH°_ | 20 unknown ± 0.4 | 796.5 | cph | experimental | [1] Zeng 1999; _cites ref. 8_ | Table 0, p. 4, row 2; `ORC-7RRDPPY2SZ` | | | Partial enthalpy; _printed: ΔH°_ | 25.16 kJ/mol-H | 976 | Liquid | experimental | [1] Zeng 1999; _cites ref. 24_ | Table 0, p. 4, row 6; `ORC-5UMAAAWGTJ` | | | Partial enthalpy; _printed: ΔH°_ | 16.7 unknown ± 0.3 | 978.5 | Liquid | experimental | [1] Zeng 1999; _cites ref. 8_ | Table 0, p. 4, row 7; `ORC-F5UODIDQA2` | | ## Sources Reporting papers the values were read from (a value cited from another work names that work in its row). 1. K Zeng, Critical assessment and thermodynamic modeling of the Mg–H system, International Journal of Hydrogen Energy 24, 989-1004 (1999). [doi:10.1016/s0360-3199(98)00132-3](https://doi.org/10.1016/s0360-3199%2898%2900132-3) ## 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=\, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).