# Si2Y: enthalpy of formation > Enthalpy of formation of Si2Y: 9 literature value(s) with sources, pages and quotes and DFT values (Materials Project / OQMD), from ORCHID. HTML: https://data.orchid-project.org/compounds/Si2Y.html · Markdown: https://data.orchid-project.org/compounds/Si2Y.md 9 accepted literature formation-enthalpy value(s) (experimental 2, model 5, DFT 2); experimental median -63.9 kJ/mol-atom (n = 2); Materials Project -48.296 kJ/mol-atom (mp-aaaaasxd); OQMD -52.293 kJ/mol-atom (oqmd-19375). Systems: [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) ## Literature values Table: Enthalpy of formation of Si2Y reported in the literature (9) | Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote | |---:|---|---:|---|---|---|---|---|---| | -66 kJ/mol-atom ± 3.4 | YSi2 | 298.15 | experimental | | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019; _cites Polotskaya 1997_ [doi](https://doi.org/10.1007/bf02676225) | Table 2, p. 3, row 1; `ORC-URIPMRCZ3I.8cc05d` | | | -61.8 kJ/mol-atom ± 1.4 | YSi2 | 298.15 | experimental | | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019; _cites Meschel 1998_ [doi](https://doi.org/10.1016/s0925-8388%2898%2900504-0) | Table 2, p. 3, row 2; `ORC-4GRDKBOGIM.4fa341` | | | -68 kJ/mol-atom | YSi2 | | model | | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019; _cites Niessen 1981_ [doi](https://doi.org/10.1016/0022-5088%2881%2990200-9) | Table 2, p. 3, row 5; `ORC-HEAPMVD35C.a085fe` | | | -60.266 kJ/mol-atom | YSi2 | | model | | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019; _cites Shukla 2009_ [doi](https://doi.org/10.3139/146.110003) | Table 2, p. 3, row 3; `ORC-5TNMRC7JAK.eb508b` | | | -54.67 kJ/mol-atom | YSi2 (R) | | model | CALPHAD | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019 | Table 3, p. 3, row 14; `ORC-WOUJPUI6TH` | | | -54.4 kJ/mol-atom | YSi2 (H) | | model | CALPHAD | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019 | Table 3, p. 3, row 12; `ORC-3NVN2XDUWX` | | | -38.9214 kJ/mol-atom | YSi2 | | model | | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019; _cites Ran 1989_ | Table 2, p. 3, row 4; `ORC-ZFKVRMRWWG.78afef` | | | -50.91 kJ/mol-atom | YSi2 (R) | 0 | DFT | First principles | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019 | Table 3, p. 3, row 13; `ORC-PXWJTJAKXJ` | | | -49.25 kJ/mol-atom | YSi2 (H) | 0 | DFT | First principles | [Si–Y](https://data.orchid-project.org/systems/SI-Y.html) | [1] Xu 2019 | Table 3, p. 3, row 11; `ORC-K47LECRQ4P` | | ### 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 Si2Y | Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective | |---:|---|---:|---:|---|---:|---:|---:|---:| | -66 | kJ/mol-atom | 3.4 | 0.05 | 3.5 (unknown, calibrated) | | | | 3.5 | | -61.8 | kJ/mol-atom | 1.4 | 0.05 | 3.5 (unknown, calibrated) | | | | 3.5 | | -68 | kJ/mol-atom | | 0.5 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -60.266 | kJ/mol-atom | | 5.000e-4 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -54.67 | kJ/mol-atom | | 0.005 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -54.4 | kJ/mol-atom | | 0.05 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -38.9214 | kJ/mol-atom | | 5.000e-5 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -50.91 | kJ/mol-atom | | 0.005 | 9.966 (dft, calibrated) | | | | 9.966 | | -49.25 | kJ/mol-atom | | 0.005 | 9.966 (dft, calibrated) | | | | 9.966 | ## 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 Si2Y | Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical | |---|---|---:|---:|---|---:|---:|---| | Materials Project | mp-aaaaasxd | -48.296 | -0.50055 | I4_1/amd | 4.2329 | 0.0439 | no | | OQMD | oqmd-19375 | -52.293 | -0.54198 | I41/amd | 7.2233 | 0.0749 | 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. Kai Xu, Houke Zou, Keke Chang, Zixuan Deng, Xiaobing Zhou, Yeyan Huang et al., Thermodynamic description of the sintering aid system in silicon carbide ceramics with the addition of yttrium, Journal of the European Ceramic Society 39, 4510-4519 (2019). [doi:10.1016/j.jeurceramsoc.2019.07.012](https://doi.org/10.1016/j.jeurceramsoc.2019.07.012) ## 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/).