N–Ta system

7 accepted literature values from 2 paper(s) (experimental 5, unspecified 2); 0 calculated phase diagram(s). 2 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: JSON · CSV · interactive explorer · phases (6) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	5
unspecified	2

Accepted values by property group
Property group	Values
phase transition	1
formation	2
crystal structure	4

Convex hulls: Materials Project DFT hull · OQMD DFT hull

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.

Enthalpies of formation, N–Ta system (2)
Phase	Compound	Value	T (K)	Class	MP DFT (kJ/mol-atom)	OQMD DFT (kJ/mol-atom)	Source	Location	Quote
TaN3	TaN3	22 kJ/mol-atom	298.15	unspecified		75.777 (oqmd-322871)	[1] Frisk 1998	Table 2, p. 7, row 1 report
TaN3	TaN3	22 kJ/mol-atom	298.15	unspecified		75.777 (oqmd-322871)	[1] Frisk 1998 cites F 1988	Table 2, p. 7, row 2 report

Other properties

Phase transition (1)

Phase transition, N–Ta system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	1950 K	1950	fcc dTaNx + hcp e-TaN	experimental	[2] Danon 2003 cites Frisk 1998 doi	p. 8 report	In this point it is worth to mention that the fcc dTaNx nitride is not stable below 1950 K in the binary Ta-N system [14]; the equilibrium phase of TaN formed at lower temperatures is hcp e-TaN.

Crystal structure (4)

Crystal structure, N–Ta system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Lattice a	5.285 Å	298.15	Ta2Nx (hcp)	experimental	[1] Frisk 1998 cites Conroy 1977 doi	Table 1, p. 2, row 1 report
Lattice a	5.196 Å	298.15	ε-TaN alloy: Ta 0.5	experimental	[1] Frisk 1998 cites Christensen 1978 doi	Table 1, p. 2, row 3 report
Lattice c	4.919 Å	298.15	Ta2Nx (hcp)	experimental	[1] Frisk 1998 cites Conroy 1977 doi	Table 1, p. 2, row 1 report
Lattice c	2.911 Å	298.15	ε-TaN alloy: Ta 0.5	experimental	[1] Frisk 1998 cites Christensen 1978 doi	Table 1, p. 2, row 3 report

Sources

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

Karin Frisk, Analysis of the phase diagram and thermochemistry in the Ta–N and the Ta–C–N systems, Journal of Alloys and Compounds 278, 216-226 (1998). doi:10.1016/s0925-8388(98)00582-9
A Danon, C Servant, Contribution to a thermodynamic database and phase equilibria calculations for low activation Ta-containing steels, Journal of Nuclear Materials 321, 8-18 (2003). doi:10.1016/s0022-3115(03)00196-x

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). doi: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). doi: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). doi: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.

@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}
}