KNa2: enthalpy of formation
2 accepted literature formation-enthalpy value(s) (experimental 1, DFT 1); experimental median -0.607 kJ/mol-atom (n = 1); Materials Project 0.954 kJ/mol-atom (mp-aaabgmji); OQMD -7.272 kJ/mol-atom (oqmd-668086).
Systems: K–Na
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -0.60668 kJ/mol-atom | KNa2 | 298.15 | experimental | K–Na | [1] Zhang 2006 cites Hultgren 1963 | Table 2, p. 3, row 31 report | ||
| -0.699 kJ/mol-atom | KNa2 | 0 | DFT | first-principle calculations | K–Na | [1] Zhang 2006 | Table 2, p. 3, row 30 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 |
|---|---|---|---|---|---|---|---|---|
| -0.60668 | kJ/mol-atom | 5.000e-6 | 3.5 (unknown, calibrated) | 3.5 | ||||
| -0.699 | kJ/mol-atom | 5.000e-4 | 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-aaabgmji | 0.954 | 0.009883 | P6_3/mmc | 0.9536 | 0.0099 | no |
| OQMD | oqmd-668086 | -7.272 | -0.075365 | P63/mmc | 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
- Shengjun Zhang, Carl Brubaker, Chao Jiang, Mei Yang, Yu Zhong, Qingyou Han et al., A combined first-principles calculation and thermodynamic modeling of the F–K–Na system, Materials Science and Engineering: A 418, 161-171 (2006). doi:10.1016/j.msea.2005.11.037