Si3N4: enthalpy of formation
2 accepted literature formation-enthalpy value(s) (experimental 1, unspecified 1); experimental median -105.097 kJ/mol-atom (n = 1); Materials Project -125.391 kJ/mol-atom (mp-aaaaabma); OQMD -117.182 kJ/mol-atom (oqmd-3591).
Systems: N–Si
Literature values
| Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote |
|---|---|---|---|---|---|---|---|---|
| -105.097 kJ/mol-atom ± 3.58286 | α-Si3N4 | 298.15 | experimental | N–Si | [1] Ma 2003 cites Pehlke 1959 | Table 2, p. 2, row 4 report | ||
| -106.393 kJ/mol-atom ± 4.18571 | α-Si3N4 | 298.15 | unspecified | N–Si | [1] Ma 2003 cites Chase 1998 | Table 2, p. 2, 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 |
|---|---|---|---|---|---|---|---|---|
| -105.097 | kJ/mol-atom | 3.583 | 7.143e-4 | 3.5 (unknown, calibrated) | 3.583 | |||
| -106.393 | kJ/mol-atom | 4.186 | 7.143e-5 | 3.5 (unknown, calibrated) | 4.186 |
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-aaaaabma | -125.391 | -1.29959 | P6_3/m | 0 | 0 | no |
| OQMD | oqmd-3591 | -117.182 | -1.21451 | P63/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
- Xiaoyan Ma, Changrong Li, Fuming Wang, Weijing Zhang, Thermodynamic assessment of the Si–N system, Calphad 27, 383-388 (2003). doi:10.1016/j.calphad.2003.12.005