ScSi: enthalpy of formation
5 accepted literature formation-enthalpy value(s) (experimental 3, model 2); experimental median -87.21 kJ/mol-atom (n = 3); Materials Project -77.326 kJ/mol-atom (mp-aaaaaotl); OQMD -80.839 kJ/mol-atom (oqmd-7936).
Systems: Sc–Si
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -117.2 kJ/mol-atom | ScSi | 298.15 | experimental | Acid solution calorimetry | Sc–Si | [1] Qin 2015 cites Golutvin 1984 | Table 2, p. 3, row 1 report | |
| -87.21 kJ/mol-atom ± 2.1 | ScSi | 935 | experimental | EMF | Sc–Si | [1] Qin 2015 cites Lukashenko 1992 doi | Table 2, p. 3, row 3 report | |
| -82.3 kJ/mol-atom ± 2.1 | ScSi | 298.15 | experimental | High temperature synthesis calorimetry | Sc–Si | [1] Qin 2015 cites Meschel 1998 doi | Table 2, p. 3, row 4 report | |
| -81.2 kJ/mol-atom | ScSi | 298.15 | model | Calculated | Sc–Si | [1] Qin 2015 | Table 2, p. 3, row 7 report | |
| -80 kJ/mol-atom | ScSi | 0 | model | Predicted | Sc–Si | [1] Qin 2015 cites Niessen 1981 | Table 2, p. 3, 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 |
|---|---|---|---|---|---|---|---|---|
| -117.2 | kJ/mol-atom | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | ||||
| -87.21 | kJ/mol-atom | 2.1 | 0.005 | 4.6 (emf, cleaned_below_threshold) | 4.6 | |||
| -82.3 | kJ/mol-atom | 2.1 | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | |||
| -81.2 | kJ/mol-atom | 0.05 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -80 | 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-aaaaaotl | -77.326 | -0.80143 | Cmcm | 0 | 0 | no |
| OQMD | oqmd-7936 | -80.839 | -0.837843 | Cmcm | 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
- Aning Qin, Dandan Liu, Chong Chen, Shuhong Liu, Yong Du, Man Wang et al., Heat contents of Sc5Si3 and ScSi intermetallics and thermodynamic modeling of the Sc–Si system, J Therm Anal Calorim 119, 1315-1321 (2015). doi:10.1007/s10973-014-4216-2