Cu2Nd: enthalpy of formation
3 accepted literature formation-enthalpy value(s) (experimental 1, model 1, DFT 1); experimental median -16.9 kJ/mol-atom (n = 1); Materials Project -19.536 kJ/mol-atom (mp-aaaaarnw); OQMD -20.057 kJ/mol-atom (oqmd-1435011).
Systems: Cu–Nd
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -16.9 kJ/mol-atom | Cu2Nd | 298.15 | experimental | Cu–Nd | [1] Wang 2011 cites Qi 1989 doi | Table 2, p. 3, row 6 report | ||
| -20.25 kJ/mol-atom | Cu2Nd | 298.15 | model | CALPHAD | Cu–Nd | [1] Wang 2011 | Table 2, p. 3, row 8 report | |
| -20.488 kJ/mol-atom | Cu2Nd | 298.15 | DFT | DFT | Cu–Nd | [1] Wang 2011 | Table 2, p. 3, row 7 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 |
|---|---|---|---|---|---|---|---|---|
| -16.9 | kJ/mol-atom | 0.05 | 3.5 (unknown, calibrated) | 3.5 | ||||
| -20.25 | kJ/mol-atom | 0.005 | 3.9 (model_calculated, calibrated) | 3.9 | ||||
| -20.488 | 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-aaaaarnw | -19.536 | -0.202477 | Imma | 0 | 0 | no |
| OQMD | oqmd-1435011 | -20.057 | -0.207875 | P6/mmm | 0 | 0 | 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
- Peisheng Wang, Liangcai Zhou, Yong Du, Honghui Xu, Shuhong Liu, Li Chen et al., Thermodynamic optimization of the Cu–Nd system, Journal of Alloys and Compounds 509, 2679-2683 (2011). doi:10.1016/j.jallcom.2010.11.160