Ca2Pb: enthalpy of formation
7 accepted literature formation-enthalpy value(s) (experimental 4, model 3); experimental median -59 kJ/mol-atom (n = 4); Materials Project -53.157 kJ/mol-atom (mp-aaaabtcg); OQMD -54.694 kJ/mol-atom (oqmd-10998).
Systems: Ca–Pb
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -62 kJ/mol-atom ± 2 | Ca2Pb | 300 | experimental | Solution calorimetry | Ca–Pb | [1] Idbenali 2008 cites Sommer 2006 doi | Table 5, p. 8, row 1 report | |
| -59 kJ/mol-atom ± 1.5 | Ca2Pb | 300 | experimental | Dissolution calorimetry | Ca–Pb | [1] Idbenali 2008 cites Bouirden 1984 | Table 5, p. 8, row 3 report | |
| -59 kJ/mol-atom ± 5 | Ca2Pb | 300 | experimental | Solution calorimetry | Ca–Pb | [1] Idbenali 2008 cites Notin 1989 doi | Table 5, p. 8, row 2 report | |
| -59 kJ/mol-atom ± 1.5 | Ca2Pb | 300 | experimental | dissolution calorimetry | Ca–Pb | [2] Cartigny 2004 cites Bouirden 1984 | Table 2, p. 3, row 7 report | |
| -69.577 kJ/mol-atom | Ca2Pb | 300 | model | Ca–Pb | [2] Cartigny 2004 | Table 2, p. 3, row 8 report | ||
| -69.577 kJ/mol-atom | Ca2Pb | 300 | model | Optimization | Ca–Pb | [1] Idbenali 2008 cites Cartigny 2004 doi | Table 5, p. 8, row 4 report | |
| -66.305 kJ/mol-atom | Ca2Pb | 300 | model | Optimization | Ca–Pb | [1] Idbenali 2008 | Table 5, p. 8, row 5 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 |
|---|---|---|---|---|---|---|---|---|
| -62 | kJ/mol-atom | 2 | 0.5 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | |||
| -59 | kJ/mol-atom | 1.5 | 0.5 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | |||
| -59 | kJ/mol-atom | 5 | 0.5 | 3.2 (solution_reaction_calorimetry, calibrated) | 5 | |||
| -59 | kJ/mol-atom | 1.5 | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | |||
| -69.577 | kJ/mol-atom | 5.000e-4 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -69.577 | kJ/mol-atom | 5.000e-4 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -66.305 | 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-aaaabtcg | -53.157 | -0.550939 | Pnma | 0 | 0 | no |
| OQMD | oqmd-10998 | -54.694 | -0.566865 | Pnma | 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
- M. Idbenali, C. Servant, N. Selhaoui, L. Bouirden, A thermodynamic reassessment of the Ca–Pb system, Calphad 32, 64-73 (2008). doi:10.1016/j.calphad.2007.10.004
- Y. Cartigny, J.M. Fiorani, A. Maı̂tre, M. Vilasi, Thermodynamic assessment of the Ca–Pb system, Thermochimica Acta 414, 197-202 (2004). doi:10.1016/j.tca.2004.01.001