LaC2: enthalpy of formation
6 accepted literature formation-enthalpy value(s) (experimental 6); experimental median -28.15 kJ/mol-atom (n = 6); Materials Project -15.461 kJ/mol-atom (mp-aaaaadnb); OQMD -16.27 kJ/mol-atom (oqmd-1979286).
Systems: C–La
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -50.3 kJ/mol-atom ± 5.3 | LaC2 | 298.15 | experimental | Langmuir evaporation | C–La | [1] Peng 2011 cites Jackson 1963 | Table 2, p. 2, row 7 report | |
| -29.7 kJ/mol-atom ± 8 | LaC2 | 298.15 | experimental | Knudsen effusion | C–La | [1] Peng 2011 cites Stearns 1971 doi | Table 2, p. 2, row 6 report | |
| -29.1 kJ/mol-atom ± 3.5 | LaC2 | 298.15 | experimental | emf | C–La | [1] Peng 2011 cites Anderson 2011 | Table 2, p. 2, row 5 report | |
| -27.2 kJ/mol-atom ± 1.4 | LaC2 | 298.15 | experimental | Calorimetry | C–La | [1] Peng 2011 cites Meschel 1994 doi | Table 2, p. 2, row 4 report | |
| -26.5 kJ/mol-atom | LaC2 | 298.15 | experimental | Knudsen effusion | C–La | [1] Peng 2011 cites Faircloth 1968 doi | Table 2, p. 2, row 3 report | |
| -19.5 kJ/mol-atom ± 3.4 | LaC2 | 298.15 | experimental | CO pressure | C–La | [1] Peng 2011 cites Vidhya 2001 doi | Table 2, p. 2, row 2 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 |
|---|---|---|---|---|---|---|---|---|
| -50.3 | kJ/mol-atom | 5.3 | 0.05 | 4.2 (kems_vapour, calibrated) | 5.3 | |||
| -29.7 | kJ/mol-atom | 8 | 0.05 | 4.2 (kems_vapour, calibrated) | 8 | |||
| -29.1 | kJ/mol-atom | 3.5 | 0.05 | 4.6 (emf, cleaned_below_threshold) | 4.6 | |||
| -27.2 | kJ/mol-atom | 1.4 | 0.05 | 3.2 (solution_reaction_calorimetry, calibrated) | 3.2 | |||
| -26.5 | kJ/mol-atom | 0.05 | 4.2 (kems_vapour, calibrated) | 4.2 | ||||
| -19.5 | kJ/mol-atom | 3.4 | 0.05 | 4.1 (experimental_unspecified, cleaned_below_threshold) | 4.1 |
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-aaaaadnb | -15.461 | -0.160246 | I4/mmm | 0 | 0 | no |
| OQMD | oqmd-1979286 | -16.27 | -0.16863 | C2/c | 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
- Yingbiao Peng, Yong Du, Lijun Zhang, Chunsheng Sha, Shuhong Liu, Feng Zheng et al., Thermodynamic modeling of the C–RE (RE=La, Ce and Pr) systems, Calphad 35, 533-541 (2011). doi:10.1016/j.calphad.2011.09.002