Fe2Hf: enthalpy of formation
8 accepted literature formation-enthalpy value(s) (experimental 2, model 6); experimental median -25.85 kJ/mol-atom (n = 2); Materials Project -33.396 kJ/mol-atom (mp-aaaaaamv); OQMD -33.317 kJ/mol-atom (oqmd-30206).
Systems: Fe–Hf
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -39.4 kJ/mol-atom ± 4.3 | Fe2Hf-HT | 1723 | experimental | Calorimetry | Fe–Hf | [1] Idbenali 2008 cites Gachon 1992 doi | Table 2, p. 3, row 1 report | |
| -12.3 kJ/mol-atom ± 1.1 | Fe2Hf-HT | 1373 | experimental | Calorimetry | Fe–Hf | [1] Idbenali 2008 cites Meschel 2006 doi | Table 2, p. 3, row 4 report | |
| -40.33 kJ/mol-atom | Fe2Hf-HT | 1723 | model | Optimization | Fe–Hf | [1] Idbenali 2008 | Table 2, p. 3, row 5 report | |
| -39.86 kJ/mol-atom | Fe2Hf-LT | 1460 | model | Optimization | Fe–Hf | [1] Idbenali 2008 | Table 2, p. 3, row 7 report | |
| -39.847 kJ/mol-atom | Fe2Hf-LT | 1480 | model | Optimization | Fe–Hf | [1] Idbenali 2008 | Table 2, p. 3, row 6 report | |
| -34.525 kJ/mol-atom | Fe2Hf-LT | 298.15 | model | Optimization | Fe–Hf | [1] Idbenali 2008 | Table 2, p. 3, row 8 report | |
| -28 kJ/mol-atom | Fe2Hf-HT | 298.15 | model | Prediction | Fe–Hf | [1] Idbenali 2008 cites Niessen 1983 doi | Table 2, p. 3, row 3 report | |
| -25 kJ/mol-atom | Fe2Hf-HT | model | Calculation | Fe–Hf | [1] Idbenali 2008 cites Colinet 1985 doi | Table 2, p. 3, 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.
| Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective |
|---|---|---|---|---|---|---|---|---|
| -39.4 | kJ/mol-atom | 4.3 | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 4.3 | |||
| -12.3 | kJ/mol-atom | 1.1 | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | |||
| -40.33 | kJ/mol-atom | 0.005 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -39.86 | kJ/mol-atom | 0.005 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -39.847 | kJ/mol-atom | 5.000e-4 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -34.525 | kJ/mol-atom | 5.000e-4 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -28 | kJ/mol-atom | 0.5 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -25 | kJ/mol-atom | 0.5 | 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-aaaaaamv | -33.396 | -0.346126 | Fd-3m | 0 | 0 | no |
| OQMD | oqmd-30206 | -33.317 | -0.345308 | 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
- M. Idbenali, N. Selhaoui, L. Bouirden, C. Servant, Thermodynamic assessment of the Fe–Hf binary system, Journal of Alloys and Compounds 456, 151-158 (2008). doi:10.1016/j.jallcom.2007.02.036