Ca14Si19: enthalpy of formation
2 accepted literature formation-enthalpy value(s) (experimental 1, model 1); experimental median -44.4 kJ/mol-atom (n = 1); Materials Project -40.575 kJ/mol-atom (mp-aaaabqxx); OQMD -45.81 kJ/mol-atom (oqmd-14227).
Systems: Ca–Si
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -44.4 kJ/mol-atom | Ca14Si19 | 298.15 | experimental | Knudsen cell | Ca–Si | [1] Gröbner 2003 cites Sudatsova 1988 | Table 1, p. 2, row 10 report | |
| -44.4 kJ/mol-atom | Ca14Si19 | 298.15 | model | Calphad | Ca–Si | [1] Gröbner 2003 | Table 1, p. 2, row 11 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 |
|---|---|---|---|---|---|---|---|---|
| -44.4 | kJ/mol-atom | 0.05 | 4.2 (kems_vapour, calibrated) | 4.2 | ||||
| -44.4 | 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-aaaabqxx | -40.575 | -0.420528 | R-3c | 0.6012 | 0.0062 | no |
| OQMD | oqmd-14227 | -45.81 | -0.474788 | R-3c | 0.2356 | 0.0024 | 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
- Joachim Gröbner, Igor Chumak, Rainer Schmid-Fetzer, Experimental study of ternary Ca–Mg–Si phase equilibria and thermodynamic assessment of Ca–Si and Ca–Mg–Si systems, Intermetallics 11, 1065-1074 (2003). doi:10.1016/j.intermet.2003.07.001