CaGa4: enthalpy of formation
2 accepted literature formation-enthalpy value(s) (experimental 1, DFT 1); experimental median -24.9 kJ/mol-atom (n = 1); Materials Project -35.27 kJ/mol-atom (mp-aaaaacya); OQMD -35.178 kJ/mol-atom (oqmd-647536).
Systems: Ca–Ga
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -24.9 kJ/mol-atom ± 4.9 | CaGa4 | 298.15 | experimental | Ca–Ga | [1] Li 2013 cites Reddy 1999 doi | Table 2, p. 3, row 12 report | ||
| -34.155 kJ/mol-atom | CaGa4 | 0 | DFT | first-principles calculations | Ca–Ga | [1] Li 2013 | Table 2, p. 3, 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 |
|---|---|---|---|---|---|---|---|---|
| -24.9 | kJ/mol-atom | 4.9 | 5.000e-4 | 3.5 (unknown, calibrated) | 4.9 | |||
| -34.155 | 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-aaaaacya | -35.27 | -0.365544 | I4/mmm | 0 | 0 | no |
| OQMD | oqmd-647536 | -35.178 | -0.364601 | C2/m | 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
- Xi Li, Kaiming Cheng, Xiaoming Yuan, Dongdong Zhao, Jinghua Xin, Weiwei Wang et al., Thermodynamic assessment of the Ga–X (X=B, Ca, Sr, Ba) systems supported by first-principles calculations, Calphad 43, 52-60 (2013). doi:10.1016/j.calphad.2013.09.002