Ga3Nb5: enthalpy of formation
5 accepted literature formation-enthalpy value(s) (experimental 2, model 2, DFT 1); experimental median -33.05 kJ/mol-atom (n = 2); Materials Project -32.041 kJ/mol-atom (mp-aaabglqj); OQMD -32.471 kJ/mol-atom (oqmd-30301).
Systems: Ga–Nb
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -39.6 kJ/mol-atom ± 1 | Ga3Nb5 | 298.15 | experimental | EMF | Ga–Nb | [1] Tamim 2023 cites Kober 1986 | Table 2, p. 8, row 12 report | |
| -26.5 kJ/mol-atom ± 1.7 | Ga3Nb5 | 1373 | experimental | Calorimetry | Ga–Nb | [1] Tamim 2023 cites Meschel 2000 doi | Table 2, p. 8, row 11 report | |
| -28.953 kJ/mol-atom | Ga3Nb5 | 298.15 | model | Ga–Nb | [1] Tamim 2023 | Table 2, p. 8, row 15 report | ||
| -27.43 kJ/mol-atom | Ga3Nb5 | 298.15 | model | Miedema | Ga–Nb | [1] Tamim 2023 cites De 1988 | Table 2, p. 8, row 14 report | |
| -32.89 kJ/mol-atom | Ga3Nb5 | 298.15 | DFT | DFT | Ga–Nb | [1] Tamim 2023 cites Colinet 2015 | Table 2, p. 8, row 13 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 |
|---|---|---|---|---|---|---|---|---|
| -39.6 | kJ/mol-atom | 1 | 0.05 | 4.6 (emf, cleaned_below_threshold) | 4.6 | |||
| -26.5 | kJ/mol-atom | 1.7 | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | |||
| -28.953 | kJ/mol-atom | 5.000e-4 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -27.43 | kJ/mol-atom | 0.005 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -32.89 | kJ/mol-atom | 0.005 | 8.395 (dft, calibrated) | 8.395 |
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-aaabglqj | -32.041 | -0.332087 | I4/mcm | 0.8134 | 0.0084 | no |
| OQMD | oqmd-30301 | -32.471 | -0.33654 | I4/mcm | 0.5007 | 0.0052 | 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