# Bi2Rb: enthalpy of formation > Enthalpy of formation of Bi2Rb: 8 literature value(s) with sources, pages and quotes and DFT values (Materials Project / OQMD), from ORCHID. HTML: https://data.orchid-project.org/compounds/Bi2Rb.html · Markdown: https://data.orchid-project.org/compounds/Bi2Rb.md 8 accepted literature formation-enthalpy value(s) (experimental 2, model 4, DFT 2); experimental median -25.9 kJ/mol-atom (n = 1); Materials Project -31.18 kJ/mol-atom (mp-aaaabikj); OQMD -29.992 kJ/mol-atom (oqmd-647552). Systems: [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) ## Literature values Table: Enthalpy of formation of Bi2Rb reported in the literature (8) | Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote | |---:|---|---:|---|---|---|---|---|---| | -25.9 kJ/mol-atom ± 2 | Bi2Rb | 298.15 | experimental | Vapor Pressure Measurements | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [1] Dziri 2022; _cites Voronin 1974_ | Table 4, p. 7, row 1; `ORC-6SOWRE2DF4.c8006f` | | | -25.9 per mol-atom ± 2 | Bi2Rb | 298.15 | experimental | | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [2] Liu 2013; _cites Voronin 1974_ | Table 3, p. 4, row 1; `ORC-FYYOWDSXY7.77a0bf` | | | -35.5 per mol-atom | Bi2Rb | 298.15 | model | | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [2] Liu 2013 | Table 3, p. 4, row 2; `ORC-CFR5WXZQMW.07b7bd` | | | -35.5 kJ/mol-atom | Bi2Rb | | model | Calphad | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [1] Dziri 2022; _cites Liu 2013_ [doi](https://doi.org/10.1016/j.tca.2013.01.029) | Table 4, p. 7, row 2; `ORC-O5IXZUV7WJ.e32f2b` | | | -34.433 kJ/mol-atom | Bi2Rb | | model | Calphad | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [1] Dziri 2022; _cites Cao 2014_ [doi](https://doi.org/10.1016/j.calphad.2014.04.001) | Table 4, p. 7, row 3; `ORC-2ZFB7HJER4.d5877b` | | | -31.917 kJ/mol-atom | Bi2Rb | | model | Calphad | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [1] Dziri 2022 | Table 4, p. 7, row 4; `ORC-63U5R4AK4D.f9cc78` | | | -35.533 kJ/mol-atom | Bi2Rb | 0 | DFT | Ab-initio LDA | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [1] Dziri 2022 | Table 4, p. 7, row 6; `ORC-Q55RWEY7ZE.2577aa` | | | -30.434 kJ/mol-atom | Bi2Rb | 0 | DFT | Ab-initio GGA | [Bi–Rb](https://data.orchid-project.org/systems/BI-RB.html) | [1] Dziri 2022 | Table 4, p. 7, row 5; `ORC-CYOIAGTFBT.9a04c2` | | ### 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 Bi2Rb | Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective | |---:|---|---:|---:|---|---:|---:|---:|---:| | -25.9 | kJ/mol-atom | 2 | 0.05 | 4.2 (kems_vapour, calibrated) | | | | 4.2 | | -25.9 | per mol-atom | 2 | 0.05 | unit 'per mol-atom' not convertible to kJ/mol-atom | | | | 2 | | -35.5 | per mol-atom | | 0.05 | unit 'per mol-atom' not convertible to kJ/mol-atom | | | | unit 'per mol-atom' not convertible to kJ/mol-atom | | -35.5 | kJ/mol-atom | | 0.05 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -34.433 | kJ/mol-atom | | 5.000e-4 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -31.917 | kJ/mol-atom | | 5.000e-4 | 3.9 (model_calculated, calibrated) | | | | 3.9 | | -35.533 | kJ/mol-atom | | 5.000e-4 | 8.395 (dft, calibrated) | | | | 8.395 | | -30.434 | kJ/mol-atom | | 5.000e-4 | 8.395 (dft, calibrated) | | | | 8.395 | ## 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 Bi2Rb | Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical | |---|---|---:|---:|---|---:|---:|---| | Materials Project | mp-aaaabikj | -31.18 | -0.323161 | Fd-3m | 0 | 0 | no | | OQMD | oqmd-647552 | -29.992 | -0.310843 | Fd-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. F. Dziri, Y. Djaballah, E. Belbacha, A. Belgacem Bouzida, Thermodynamic Reassessment of the Bi-Rb System Supported by Ab-Initio Calculations, J. Phase Equilib. Diffus. 43, 382-392 (2022). [doi:10.1007/s11669-022-00968-3](https://doi.org/10.1007/s11669-022-00968-3) 2. Miao Liu, Changrong Li, Zhenmin Du, Cuiping Guo, Chunju Niu, Thermodynamic assessment of the Bi–Rb binary system, Thermochimica Acta 551, 27-32 (2013). [doi:10.1016/j.tca.2012.10.012](https://doi.org/10.1016/j.tca.2012.10.012) ## 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/).