Al4Cr: enthalpy of formation

4 accepted literature formation-enthalpy value(s) (experimental 2, model 2); experimental median -17.152 kJ/mol-atom (n = 2); OQMD -6.536 kJ/mol-atom (oqmd-2163960).

Systems: Al–Cr

Literature values

Enthalpy of formation of Al4Cr reported in the literature (4)
Value	Phase as printed	T (K)	Class	System	Source	Location
-17.154 kJ/mol-atom	Al4Cr	298.15	experimental	Al–Cr	[1] Murray 1998 cites ref. 60Kub	Table 4, p. 6, row 3 report
-17.15 kJ/mol-atom	Al4Cr	1273.15	experimental	Al–Cr	[2] Saunders 1986 cites ref. 35	Table 1, p. 4, row 5 report
-17.68 kJ/mol-atom	Al4Cr	1273.15	model	Al–Cr	[2] Saunders 1986	Table 1, p. 4, row 6 report
-17.677 kJ/mol-atom	Al4Cr	1	model	Al–Cr	[2] Saunders 1986	Table 4, p. 8, row 3 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 Al4Cr
Value	Unit	Reading	Method (class, basis)	Effective
-17.154	kJ/mol-atom	5.000e-4	3.5 (unknown, calibrated)	3.5
-17.15	kJ/mol-atom	0.005	3.5 (unknown, calibrated)	3.5
-17.68	kJ/mol-atom	0.005	3.9 (model_calculated, calibrated)	3.9
-17.677	kJ/mol-atom	5.000e-4	3.9 (model_calculated, calibrated)	3.9

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 Al4Cr
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
OQMD	oqmd-2163960	-6.536	-0.067738	I4/m	6.2796	0.0651	yes

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

J. L. Murray, The Al-Cr (aluminum-chromium) system, JPE 19, 367-375 (1998). doi:10.1007/bf02735058
N. Saunders, V. G. Rivlin, Thermodynamic characterization of Al–Cr, Al–Zr, and Al–Cr–Zr alloy systems, Materials Science and Technology 2, 520-527 (1986). doi:10.1179/mst.1986.2.6.520

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}
}