Cr2Ta: enthalpy of formation
5 accepted literature formation-enthalpy value(s) (experimental 2, model 3); experimental median -8.5 kJ/mol-atom (n = 1); Materials Project -11.01 kJ/mol-atom (mp-aaaaadnt); OQMD -12.142 kJ/mol-atom (oqmd-18299).
Systems: Cr–Ta
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -8.5 kJ/mol-atom ± 0.5 | Cr2Ta (LT) | 1693 | experimental | Cr–Ta | [1] Dupin 1993 cites Feschotte 1964 doi | Table 4, p. 5, row 1 report | ||
| -8.5 kJ/mol (basis unstated) | Cr2Ta C14 | 298.15 | experimental | Experiment | Cr–Ta | [2] Pavlů 2009 cites Feschotte 1964 | Table 4, p. 4, row 5 report | |
| -8.93 kJ/mol-atom | Cr2Ta (LT) | model | Cr–Ta | [1] Dupin 1993 | Table 4, p. 5, row 3 report | |||
| -8.596 kJ/mol-atom | Cr2Ta (LT) | model | Cr–Ta | [1] Dupin 1993 | Table 4, p. 5, row 4 report | |||
| -5 kJ/mol-atom | Cr2Ta (LT) | 1693 | model | Cr–Ta | [1] Dupin 1993 cites Kaufman 1991 doi | Table 4, p. 5, 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 |
|---|---|---|---|---|---|---|---|---|
| -8.5 | kJ/mol-atom | 0.5 | 5.000e-4 | 3.5 (unknown, calibrated) | 3.5 | |||
| -8.5 | kJ/mol (basis unstated) | 0.05 | 12.3 (experimental_unspecified, cleaned_below_threshold) | 12.3 | ||||
| -8.93 | kJ/mol-atom | 5.000e-4 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -8.596 | kJ/mol-atom | 5.000e-4 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -5 | 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-aaaaadnt | -11.01 | -0.114112 | Fd-3m | 0 | 0 | no |
| OQMD | oqmd-18299 | -12.142 | -0.125838 | 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
- N. Dupin, I. Ansara, Thermodynamic assessment of the Cr-Ta system, JPE 14, 451-456 (1993). doi:10.1007/bf02671963
- J. Pavlů, J. Vřešt’ál, M. Šob, Re-modeling of Laves phases in the Cr–Nb and Cr–Ta systems using first-principles results, Calphad 33, 179-186 (2009). doi:10.1016/j.calphad.2008.04.006