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 Al7Cr
Value
Unit
Printed
Reading
Method (class, basis)
Composition
Scatter
Conversion
Effective
-13.389
kJ/mol-atom
5.000e-4
3.5 (unknown, calibrated)
3.5
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 Al7Cr
Source
Entry
kJ/mol-atom
eV/atom
Space group
E above hull (kJ/mol-atom)
E above hull (eV/atom)
Theoretical
OQMD
oqmd-2166350
2.914
0.030198
R-3m
13.4992
0.1399
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