# N–Si system

> N–Si system: 34 accepted literature values (crystal structure 16, invariant reaction 7, heat capacity / entropy / enthalpy 6, formation 4) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/N-SI.html · Markdown: https://data.orchid-project.org/systems/N-SI.md

34 accepted literature values from 1 paper(s) (experimental 26, model 4, unspecified 4); 0 calculated phase diagram(s). 3 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: [JSON](https://data.orchid-project.org/literature/systems/N-SI.json) · [CSV](https://data.orchid-project.org/systems/N-SI.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#N-SI) · [phases (8)](https://data.orchid-project.org/phases/pages/N-SI.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/N-SI.html) · [Markdown](https://data.orchid-project.org/systems/N-SI.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 26 |
| model | 4 |
| unspecified | 4 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 7 |
| phase transition | 1 |
| formation | 4 |
| heat capacity / entropy / enthalpy | 6 |
| crystal structure | 16 |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/N/N-SI.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/N/N-SI.json) · [CALPHAD hull SiN-03Ma-LB](https://data.orchid-project.org/hulls/calphad-sgte/N/N-SI--SiN-03Ma-LB.json) · [CALPHAD hull SiN-92Hil](https://data.orchid-project.org/hulls/calphad-sgte/N/N-SI--SiN-92Hil.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the N–Si system (7)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 2151 | Liquid + gas \<-> Si3N4 | Si3N4: N 0.571429 | experimental | [1] Ma 2003; _cites Chase 1998_ | Table 4, p. 5, row 5; `ORC-4GAIUV5LSA` |  |
| 2150 | Liquid + gas \<-> Si3N4 | Si3N4: N 0.571429 | experimental | [1] Ma 2003; _cites Dorner 1981_ [doi](https://doi.org/10.1007/bf00542737) | Table 4, p. 5, row 6; `ORC-26V5FOWT2X` |  |
| 2150 | Liquid + gas \<-> Si3N4 | L: N 0.00145; Si3N4: N 0.571429 | model | [1] Ma 2003 | Table 4, p. 5, row 7; `ORC-UQVVWG2P6T` |  |
| 2129 | Liquid + gas \<-> Si3N4 | Si3N4: N 0.571429 | experimental | [1] Ma 2003; _cites Kaiser 1959_ [doi](https://doi.org/10.1063/1.1735180) | Table 4, p. 5, row 4; `ORC-RK2V67VXLD` |  |
| 1687 | Liquid \<-> diamond_Si + Si3N4 | L: N 2.000e-4; diamond_Si: N 0; Si3N4: N 0.571429 | experimental | [1] Ma 2003; _cites Kaiser 1959_ [doi](https://doi.org/10.1063/1.1735180) | Table 4, p. 5, row 1; `ORC-3H4KZFP6TI` |  |
| 1687 | Liquid \<-> diamond_Si + Si3N4 | L: N 1.200e-4; diamond_Si: N 0; Si3N4: N 0.571429 | experimental | [1] Ma 2003; _cites Yatsurugi 1973_ [doi](https://doi.org/10.1149/1.2403610) | Table 4, p. 5, row 2; `ORC-MWNU5ADCIS` |  |
| 1686.94 | Liquid \<-> diamond_Si + Si3N4 | L: N 0.0012; diamond_Si: N 0; Si3N4: N 0.571429 | model | [1] Ma 2003 | Table 4, p. 5, row 3; `ORC-X7BIQO7EAB` |  |

## Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from [dft_parity.json](https://data.orchid-project.org/literature/dft_parity.json).

Table: Enthalpies of formation, N–Si system (4)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| α |  | -744.752 unknown ± 29.3 | 298.15 | unspecified |  |  | [1] Ma 2003; _cites Chase 1998_ | Table 2, p. 2, row 5; `ORC-JX64R4RFLZ.7cb919` |  |
| α |  | -735.68 unknown ± 25.08 | 298.15 | experimental |  |  | [1] Ma 2003; _cites Pehlke 1959_ | Table 2, p. 2, row 4; `ORC-7EFEZK2TDU.f067de` |  |
| α-Si3N4 | [Si3N4](https://data.orchid-project.org/compounds/Si3N4.html) | -106.393 kJ/mol-atom ± 4.18571 | 298.15 | unspecified | -125.391 (mp-aaaaabma) | -117.182 (oqmd-3591) | [1] Ma 2003; _cites Chase 1998_ | Table 2, p. 2, row 5; `ORC-JX64R4RFLZ.afb0e6` |  |
| α-Si3N4 | [Si3N4](https://data.orchid-project.org/compounds/Si3N4.html) | -105.097 kJ/mol-atom ± 3.58286 | 298.15 | experimental | -125.391 (mp-aaaaabma) | -117.182 (oqmd-3591) | [1] Ma 2003; _cites Pehlke 1959_ | Table 2, p. 2, row 4; `ORC-7EFEZK2TDU.32710c` |  |

## Other properties

### Phase transition (1)

Table: Phase transition, N–Si system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase transition | 1687 K | 1687 | liquid | experimental | [1] Ma 2003; _cites Kaiser 1959_ [doi](https://doi.org/10.1063/1.1735180) | p. 1; `ORC-V54MI6EVWW` | “Using zone-melting experiments, Kaiser and Thurmond \[10\] and Yatsurugi et al. \[11\] measured the distribution of N between solid and liquid semiconductor-grade Si near its melting point (1687 K).” |

### Heat capacity / entropy / enthalpy (6)

Table: Heat capacity / entropy / enthalpy, N–Si system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Entropy; _printed: S298 K_ | 9.17143 J/mol-atom/K | 298.15 | Si3N4; _alloy: Si 0.428571_ | model | [1] Ma 2003; _cites Koshchenko 1985_ | Table 2, p. 2, row 3; `ORC-YVLSQCAPVO.17f18f` |  |
| Entropy; _printed: S298 K_ | 64.2 J/mol (basis unstated)/K | 298.15 | Si3N4 | model | [1] Ma 2003; _cites Koshchenko 1985_ | Table 2, p. 2, row 3; `ORC-YVLSQCAPVO.61ec32` |  |
| Entropy; _printed: S298 K_ | 112.967 unknown ± 16.7 | 298.15 | α | unspecified | [1] Ma 2003; _cites Chase 1998_ | Table 2, p. 2, row 2; `ORC-5EQMMJRUQZ.31bd50` |  |
| Entropy; _printed: S298 K_ | 107.008 J/mol (basis unstated)/K | 298.15 | α | experimental | [1] Ma 2003; _cites Pehlke 1959_ | Table 2, p. 2, row 1; `ORC-7Y3UKOYUWX.5e224c` |  |
| Entropy; _printed: S298 K_ | 16.1381 J/mol-atom/K ± 2.38571 | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | unspecified | [1] Ma 2003; _cites Chase 1998_ | Table 2, p. 2, row 2; `ORC-5EQMMJRUQZ.39fae7` |  |
| Entropy; _printed: S298 K_ | 15.2869 J/mol-atom/K | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Pehlke 1959_ | Table 2, p. 2, row 1; `ORC-7Y3UKOYUWX.ff192f` |  |

### Crystal structure (16)

Table: Crystal structure, N–Si system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Lattice a | 7.595 Å |  | β-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Grun 1979_ [doi](https://doi.org/10.1107/s0567740879004933) | Table 1, p. 2, row 8; `ORC-5OGNIP7D3E.613393` |  |
| Lattice a | 7.606 Å ± 0.003 |  | β-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Ruddlesden 1958_ [doi](https://doi.org/10.1107/s0365110x58001304) | Table 1, p. 2, row 7; `ORC-LDDPN2N66Z.eed9ea` |  |
| Lattice a | 7.608 Å |  | β-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Arrowsmith 1963_ | Table 1, p. 2, row 6; `ORC-OSSJA4KMCA.74cc7a` |  |
| Lattice a | 7.748 Å | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Arrowsmith 1963_ | Table 1, p. 2, row 1; `ORC-7RYBEMLQJA.8704ff` |  |
| Lattice a | 7.766 Å | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Kohatsu 1974_ [doi](https://doi.org/10.1016/0025-5408%2874%2990170-6) | Table 1, p. 2, row 4; `ORC-BBO3WESS6D.743c46` |  |
| Lattice a | 7.753 Å ± 0.004 | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Ruddlesden 1958_ [doi](https://doi.org/10.1107/s0365110x58001304) | Table 1, p. 2, row 2; `ORC-VN6ETUYGQ4.a01c0e` |  |
| Lattice a | 7.818 Å ± 0.003 | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Kato 1975_ | Table 1, p. 2, row 5; `ORC-YCL7YH4PF2.d2f55c` |  |
| Lattice a | 7.765 Å | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Marchand 1969_ [doi](https://doi.org/10.1107/s0567740869005292) | Table 1, p. 2, row 3; `ORC-Z6OT6ZIKG4.8f6a22` |  |
| Lattice c | 2.9023 Å |  | β-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Grun 1979_ [doi](https://doi.org/10.1107/s0567740879004933) | Table 1, p. 2, row 8; `ORC-5OGNIP7D3E.95b62d` |  |
| Lattice c | 2.909 Å ± 0.002 |  | β-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Ruddlesden 1958_ [doi](https://doi.org/10.1107/s0365110x58001304) | Table 1, p. 2, row 7; `ORC-LDDPN2N66Z.90be32` |  |
| Lattice c | 2.9107 Å |  | β-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Arrowsmith 1963_ | Table 1, p. 2, row 6; `ORC-OSSJA4KMCA.e48eda` |  |
| Lattice c | 5.617 Å | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Arrowsmith 1963_ | Table 1, p. 2, row 1; `ORC-7RYBEMLQJA.de056c` |  |
| Lattice c | 5.615 Å | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Kohatsu 1974_ [doi](https://doi.org/10.1016/0025-5408%2874%2990170-6) | Table 1, p. 2, row 4; `ORC-BBO3WESS6D.780149` |  |
| Lattice c | 5.618 Å ± 0.004 | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Ruddlesden 1958_ [doi](https://doi.org/10.1107/s0365110x58001304) | Table 1, p. 2, row 2; `ORC-VN6ETUYGQ4.82133b` |  |
| Lattice c | 5.591 Å ± 0.004 | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Kato 1975_ | Table 1, p. 2, row 5; `ORC-YCL7YH4PF2.d2e796` |  |
| Lattice c | 5.622 Å | 298.15 | α-Si3N4; _alloy: Si 0.428571_ | experimental | [1] Ma 2003; _cites Marchand 1969_ [doi](https://doi.org/10.1107/s0567740869005292) | Table 1, p. 2, row 3; `ORC-Z6OT6ZIKG4.770119` |  |

## Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

1. 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](https://doi.org/10.1016/j.calphad.2003.12.005)

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735569
- R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). https://doi.org/10.5281/zenodo.23735891
- R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23736065

Also cite the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0); B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file.

Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

```bibtex
@misc{orchid_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}
```

---

Derived data CC BY 4.0 ([licence](https://creativecommons.org/licenses/by/4.0/)): cite ORCHID ([CITATION.cff](https://data.orchid-project.org/CITATION.cff)) and the original sources. Quotes are short excerpts kept so that each value can be checked; they remain under the publishers' copyright and are not relicensed. Source papers, page images and full text are not redistributed. Field reference: [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt). Found an error? The report link of a value (Markdown: its id, ORC-..., in the Location column) opens a pre-filled GitHub issue, https://github.com/orchid-calphad/orchid-data/issues/new?template=report-value-error.yml&record_id=\<id>, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).