Cr3Ge: enthalpy of formation
4 accepted literature formation-enthalpy value(s) (experimental 2, model 2); experimental median -19.21 kJ/mol-atom (n = 2); Materials Project -10.8 kJ/mol-atom (mp-aaaabepp); OQMD -12.732 kJ/mol-atom (oqmd-647110).
Systems: Cr–Ge
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -19.3 kJ/mol-atom ± 2.5 | Cr3Ge | 298.15 | experimental | Knudsen effusion mass spectrometry | Cr–Ge | [1] Liu 2010 cites Zarembo 2001 doi | Table 4, p. 7, row 1 report | |
| -19.12 kJ/mol-atom | Cr3Ge | 298.15 | experimental | Potentiometric method | Cr–Ge | [1] Liu 2010 cites Lukashenko 1974 | Table 4, p. 7, row 2 report | |
| -19.3 unspecified ± 2.5 | Cr3Ge | 298.15 | model | Cr–Ge | [1] Liu 2010 cites Zarembo 2001 doi | p. 3 report | The reported standard enthalpies of formation at 298 K are -19.3 ± 2.5 kJ/mol atom for Cr0.75 Ge0.25 (Cr3 Ge) and -12.3 ± 2.5 kJ/mol-atom for Cr0.63 Ge0.37 (Cr5 Ge3 ). | |
| -15.33 kJ/mol-atom | Cr3Ge | 298.15 | model | Thermodynamic optimization | Cr–Ge | [1] Liu 2010 | Table 4, p. 7, row 3 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 |
|---|---|---|---|---|---|---|---|---|
| -19.3 | kJ/mol-atom | 2.5 | 0.05 | 4.2 (kems_vapour, calibrated) | 4.2 | |||
| -19.12 | kJ/mol-atom | 0.005 | 4.6 (emf, cleaned_below_threshold) | 4.6 | ||||
| -19.3 | unspecified | 2.5 | 0.05 | unit 'unspecified' not convertible to kJ/mol-atom | 2.5 | |||
| -15.33 | kJ/mol-atom | 0.005 | 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-aaaabepp | -10.8 | -0.111936 | Pm-3n | 0 | 0 | no |
| OQMD | oqmd-647110 | -12.732 | -0.131958 | Pm-3n | 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
- Y.Q. Liu, Y. Du, Thermodynamic description of the Cr–Ge system, Calphad 34, 26-35 (2010). doi:10.1016/j.calphad.2009.11.001