Bi2K3: enthalpy of formation
2 accepted literature formation-enthalpy value(s) (experimental 1, model 1); experimental median -39.5 kJ/mol-atom (n = 1); Materials Project -31.875 kJ/mol-atom (mp-aaacqqwr); OQMD -33.986 kJ/mol-atom (oqmd-1435539).
Systems: Bi–K
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -39.5 kJ/mol-atom ± 2.2 | Bi2K3 | 523 | experimental | Bi–K | [1] Niu 2012 cites Voronin 1971 | Table 3, p. 4, row 12 report | ||
| -43.2 kJ/mol-atom | Bi2K3 | 523 | model | Bi–K | [1] Niu 2012 | Table 3, p. 4, row 14 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 |
|---|---|---|---|---|---|---|---|---|
| -39.5 | kJ/mol-atom | 2.2 | 0.05 | 3.5 (unknown, calibrated) | 3.5 | |||
| -43.2 | kJ/mol-atom | 0.05 | 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-aaacqqwr | -31.875 | -0.330358 | C2/c | 2.4712 | 0.0256 | yes |
| OQMD | oqmd-1435539 | -33.986 | -0.35224 | C2/c | 2.4541 | 0.0254 | yes |
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
- Chunju Niu, Changrong Li, Zhenmin Du, Cuiping Guo, Miao Liu, Thermodynamic assessment of the Bi–K binary system, Thermochimica Acta 528, 9-14 (2012). doi:10.1016/j.tca.2011.10.032