Ga4Nb5: enthalpy of formation
2 accepted literature formation-enthalpy value(s) (model 2); Materials Project -33.577 kJ/mol-atom (mp-aaaabaro); OQMD -33.569 kJ/mol-atom (oqmd-17262).
Systems: Ga–Nb
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -33.02 kJ/mol-atom | Ga4Nb5 | 298.15 | model | Ga–Nb | [1] Tamim 2023 | Table 2, p. 8, row 10 report | ||
| -29.575 kJ/mol-atom | Ga4Nb5 | 298.15 | model | Miedema | Ga–Nb | [1] Tamim 2023 cites De 1988 | Table 2, p. 8, 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 |
|---|---|---|---|---|---|---|---|---|
| -33.02 | kJ/mol-atom | 0.005 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -29.575 | 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-aaaabaro | -33.577 | -0.347999 | P6_3/mcm | 0.7976 | 0.0083 | no |
| OQMD | oqmd-17262 | -33.569 | -0.347915 | P63/mcm | 0.9888 | 0.0102 | 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
- Rkia Tamim, Olivier Rapaud, Rémy Boulesteix, Alexandre Maître, Thermodynamic assessment of the Ga–Gd, Ga–Nb and Gd–Nb binary phase diagrams towards the Ga–Gd–Nb system, Calphad 82, 102596 (2023). doi:10.1016/j.calphad.2023.102596