AlCr2: enthalpy of formation
2 accepted literature formation-enthalpy value(s) (experimental 1, model 1); experimental median -10.878 kJ/mol-atom (n = 1); Materials Project -11.845 kJ/mol-atom (mp-aaaaacnj); OQMD -13.209 kJ/mol-atom (oqmd-10426).
Systems: Al–Cr
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -10.878 kJ/mol-atom | AlCr2 | 298.15 | experimental | Al–Cr | [1] Murray 1998 cites ref. 60Kub | Table 4, p. 6, row 6 report | ||
| -12.954 kJ/mol-atom | AlCr2 | 1 | model | Al–Cr | [2] Saunders 1986 | Table 4, p. 8, row 7 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.
| Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective |
|---|---|---|---|---|---|---|---|---|
| -10.878 | kJ/mol-atom | 5.000e-4 | 3.5 (unknown, calibrated) | 3.5 | ||||
| -12.954 | 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.
| Source | Entry | kJ/mol-atom | eV/atom | Space group | E above hull (kJ/mol-atom) | E above hull (eV/atom) | Theoretical |
|---|---|---|---|---|---|---|---|
| Materials Project | mp-aaaaacnj | -11.845 | -0.122767 | I4/mmm | 0 | 0 | no |
| OQMD | oqmd-10426 | -13.209 | -0.136905 | I4/mmm | 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
- 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