Mg2Y: enthalpy of formation
4 accepted literature formation-enthalpy value(s) (experimental 3, model 1); experimental median -14.2 kJ/mol-atom (n = 3); Materials Project -8.564 kJ/mol-atom (mp-aaacppey); OQMD -9.233 kJ/mol-atom (oqmd-35188).
Systems: Mg–Y
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -17.7 kJ/mol-atom | YMg2 | 298.15 | experimental | calorimetry | Mg–Y | [1] Fabrichnaya 2003 cites Bonhomme 1996 doi | Table 4, p. 5, row 8 report | |
| -14.2 kJ/mol-atom | YMg2 | 298.15 | experimental | calorimetry | Mg–Y | [1] Fabrichnaya 2003 cites Smith 1965 | Table 4, p. 5, row 6 report | |
| -12 kJ/mol-atom | YMg2 | 298.15 | experimental | calorimetry | Mg–Y | [1] Fabrichnaya 2003 cites Pyagai 1990 | Table 4, p. 5, row 7 report | |
| -12.6 kJ/mol-atom | YMg2 | model | Calphad | Mg–Y | [1] Fabrichnaya 2003 | Table 4, p. 5, row 9 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 |
|---|---|---|---|---|---|---|---|---|
| -17.7 | kJ/mol-atom | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | ||||
| -14.2 | kJ/mol-atom | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | ||||
| -12 | kJ/mol-atom | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | ||||
| -12.6 | kJ/mol-atom | 0.05 | 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-aaacppey | -8.564 | -0.088758 | Fd-3m | 0.8393 | 0.0087 | yes |
| OQMD | oqmd-35188 | -9.233 | -0.095697 | R32 | 0.1757 | 0.0018 | 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
- O.B Fabrichnaya, H.L Lukas, G Effenberg, F Aldinger, Thermodynamic optimization in the Mg–Y system, Intermetallics 11, 1183-1188 (2003). doi:10.1016/s0966-9795(03)00156-0