Bi2Cs: enthalpy of formation

4 accepted literature formation-enthalpy value(s) (experimental 1, model 1, DFT 2); experimental median -26.2 kJ/mol-atom (n = 1); Materials Project -29.714 kJ/mol-atom (mp-aaaabigx); OQMD -29.789 kJ/mol-atom (oqmd-647553).

Systems: Bi–Cs

Literature values

Enthalpy of formation of Bi2Cs reported in the literature (4)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-26.2 kJ/mol-atom	Bi2Cs	298.15	experimental	EMF	Bi–Cs	[1] Djaballah 2015 cites Voronin 1975	Table 2, p. 4, row 1 report
-31.027 kJ/mol-atom	Bi2Cs		model	CALPHAD	Bi–Cs	[1] Djaballah 2015	Table 2, p. 4, row 4 report
-37.753 kJ/mol-atom	Bi2Cs	0	DFT	LDA	Bi–Cs	[1] Djaballah 2015	Table 2, p. 4, row 3 report
-30.442 kJ/mol-atom	Bi2Cs	0	DFT	GGA	Bi–Cs	[1] Djaballah 2015	Table 2, p. 4, row 2 report

Uncertainty budget

Components kept separate, in the value's unit (literature SCHEMA.md, 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.

Uncertainty budget of the literature values of Bi2Cs
Value	Unit	Reading	Method (class, basis)	Effective
-26.2	kJ/mol-atom	0.05	4.6 (emf, cleaned_below_threshold)	4.6
-31.027	kJ/mol-atom	5.000e-4	3.9 (model_calculated, calibrated)	3.9
-37.753	kJ/mol-atom	5.000e-4	8.395 (dft, calibrated)	8.395
-30.442	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.

DFT formation energy of Bi2Cs
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaabigx	-29.714	-0.307966	Fd-3m	0	0	no
OQMD	oqmd-647553	-29.789	-0.308743	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 (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 (CC BY 4.0);

Sources

Y. Djaballah, A. Said Amer, Ş. Uğur, G. Uğur, A. Hidoussi, A. Belgacem-Bouzida, Thermodynamic description of the Bi–Cs and Bi–Tm system supported by first-principles calculations, Calphad 48, 72-78 (2015). doi:10.1016/j.calphad.2014.11.002

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). doi: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). doi: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). doi: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.

@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}
}