H–Ti system

86 accepted literature values from 3 paper(s) (experimental 7, model 27, DFT 41, unspecified 11); 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 · CSV · interactive explorer · phases (7) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	7
model	27
DFT	41
unspecified	11

Accepted values by property group
Property group	Values
invariant reaction	10
formation	25
heat capacity / entropy / enthalpy	9
crystal structure	42

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull TiH-00Koe · CALPHAD hull TiH-07Uki · CALPHAD hull TiH-08Qiu · CALPHAD hull TiH-87Kiv

Invariant reactions (literature)

Invariant reactions reported in the literature for the H–Ti system (10)
T (K)	Reaction / phases	Class	Source	Location
1070.33	δ <=> β + liquid	model	[1] Wang 2010	Table 4, p. 5, row 9 report
1070.15	δ <=> β + liquid	unspecified	[1] Wang 2010 cites Yuh 1991	Table 4, p. 5, row 10 report
725.47	eutectic: L1 -> L2(H2) + δ	model	[1] Wang 2010	Table 4, p. 5, row 7 report
720	eutectic: L1 -> L2(H2) + δ	unspecified	[1] Wang 2010 cites Yuh 1991	Table 4, p. 5, row 8 report
586.16	β <=> α + δ	model	[1] Wang 2010	Table 4, p. 5, row 1 report
580.16	β <=> α + δ	unspecified	[1] Wang 2010 cites Shusuke 2007	Table 4, p. 5, row 4 report
571.98	β <=> α + δ	model	[1] Wang 2010 cites Caian 2008	Table 4, p. 5, row 5 report
561.32	β <=> α + δ	model	[1] Wang 2010 cites E Konigsberger 2000	Table 4, p. 5, row 3 report
554	β <=> α + δ	experimental	[1] Wang 2010 cites Mcquillan 1950	Table 4, p. 5, row 6 report
552.8	β <=> α + δ	unspecified	[1] Wang 2010 cites Kivilahti 1987 doi	Table 4, p. 5, row 2 report

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, H–Ti system (23)
Phase	Value	T (K)	Class	Source	Location
TiH2	-179 kJ/mol (basis unstated)	298.15	experimental	[1] Wang 2010 cites Dantzer 1983 doi	Table 3, p. 4, row 1 report
TiH2	-165 kJ/mol (basis unstated)		unspecified	[1] Wang 2010 cites Wang 1996	Table 3, p. 4, row 4 report
TiH2	-151.2 kJ/mol (basis unstated) (range -179 to -123.4)	298.15	experimental	[2] Königsberger 2000 cites San-Martin 1987	Table 2, p. 2, row 11 report
TiH2	-148 kJ/mol (basis unstated)		unspecified	[1] Wang 2010 cites Tokujiro 2001	Table 3, p. 4, row 5 report
TiH2	-146 kJ/mol (basis unstated)		model	[1] Wang 2010 cites Caian 2008	Table 3, p. 4, row 9 report
TiH2	-142 kJ/mol (basis unstated)		model	[1] Wang 2010	Table 3, p. 4, row 10 report
TiH2	-139 kJ/mol (basis unstated)		model	[1] Wang 2010 cites E Konigsberger 2000	Table 3, p. 4, row 7 report
TiH2	-137 kJ/mol (basis unstated)	298.15	experimental	[1] Wang 2010 cites Takeuchi 1966	Table 3, p. 4, row 2 report
TiH2	-136.95 kJ/mol (basis unstated)	298.15	experimental	[2] Königsberger 2000 cites Dantzer 1983	Table 2, p. 2, row 10 report
TiH2	-134 kJ/mol (basis unstated)		unspecified	[1] Wang 2010 cites Shusuke 2007	Table 3, p. 4, row 8 report
TiH2	-133.2 kJ/mol (basis unstated)		model	[2] Königsberger 2000	Table 2, p. 2, row 9 report
TiH2	-129 kJ/mol (basis unstated)		model	[1] Wang 2010 cites Kivilahti 1987 doi	Table 3, p. 4, row 6 report
α	-28.63 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 39 report
α	-11.99 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 36 report
α	2.524 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 44 report
β	-46.4 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 48 report
β	-36.3 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 47 report
β	-26.4 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 49 report
β	-16.4 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 46 report
β	1.3 kJ/mol (basis unstated)		DFT	[3] Ukita 2007	Table 1, p. 4, row 50 report
γ-TiH	-35.66 kJ/mol (basis unstated)		model	[3] Ukita 2007	Table 2, p. 5, row 1 report
δ-TiH2	-47.1 kJ/mol (basis unstated)		model	[3] Ukita 2007	Table 2, p. 5, row 2 report
ε-TiH2	-47.3 kJ/mol (basis unstated)		model	[3] Ukita 2007	Table 2, p. 5, row 3 report

Other properties

Formation (2)

Formation, H–Ti system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Entropy of formation printed: ΔfS° (TiH2)	-136.02 J/mol (basis unstated)/K		TiH2 alloy: Ti 0.333333	model	[2] Königsberger 2000	Table 2, p. 2, row 12 report
Entropy of formation printed: ΔfS° (TiH2)	-135.25 J/mol (basis unstated)/K (range -145 to -125.5)	298.15	TiH2 alloy: Ti 0.333333	experimental	[2] Königsberger 2000 cites San-Martin 1987	Table 2, p. 2, row 13 report

Heat capacity / entropy / enthalpy (9)

Heat capacity / entropy / enthalpy, H–Ti system
Property	Value	Phases / composition	Class	Source	Location
Entropy printed: ΔSf0(TiH2)	-145 J mol-1 K-1	TiH2 alloy: Ti 0.333333	experimental	[1] Wang 2010 cites Dantzer 1983 doi	Table 3, p. 4, row 1 report
Entropy printed: ΔSf0(TiH2)	-174 J mol-1 K-1	TiH2 alloy: Ti 0.333333	unspecified	[1] Wang 2010 cites Wang 1996	Table 3, p. 4, row 4 report
Entropy printed: ΔSf0(TiH2)	-139 J mol-1 K-1	TiH2 alloy: Ti 0.333333	model	[1] Wang 2010	Table 3, p. 4, row 10 report
Entropy printed: ΔSf0(TiH2)	-145 J mol-1 K-1	TiH2 alloy: Ti 0.333333	model	[1] Wang 2010 cites Caian 2008	Table 3, p. 4, row 9 report
Entropy printed: ΔSf0(TiH2)	-142 J mol-1 K-1	TiH2 alloy: Ti 0.333333	unspecified	[1] Wang 2010 cites San-Martin 1987 doi	Table 3, p. 4, row 3 report
Entropy printed: ΔSf0(TiH2)	-136 J mol-1 K-1	TiH2 alloy: Ti 0.333333	unspecified	[1] Wang 2010 cites Shusuke 2007	Table 3, p. 4, row 8 report
Entropy printed: ΔSf0(TiH2)	-130 J mol-1 K-1	TiH2 alloy: Ti 0.333333	model	[1] Wang 2010 cites Kivilahti 1987 doi	Table 3, p. 4, row 6 report
Entropy printed: ΔSf0(TiH2)	-152 J mol-1 K-1	TiH2 alloy: Ti 0.333333	unspecified	[1] Wang 2010 cites Tokujiro 2001	Table 3, p. 4, row 5 report
Entropy printed: ΔSf0(TiH2)	-136 J mol-1 K-1	TiH2 alloy: Ti 0.333333	model	[1] Wang 2010 cites E Konigsberger 2000	Table 3, p. 4, row 7 report

Crystal structure (42)

Crystal structure, H–Ti system
Property	Value	Phases / composition	Class	Source	Location
Lattice a printed: lattice parameter a	3.016 Å	α alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 39 report
Lattice a printed: lattice parameter a	2.871 Å	α alloy: H 0.25, Ti 0.75	DFT	[3] Ukita 2007	Table 1, p. 4, row 36 report
Lattice a printed: lattice parameter a	6.449 Å	β alloy: H 0.8, Ti 0.2	DFT	[3] Ukita 2007	Table 1, p. 4, row 50 report
Lattice a printed: lattice parameter a	3.194 Å	β alloy: H 0.75, Ti 0.25	DFT	[3] Ukita 2007	Table 1, p. 4, row 49 report
Lattice a printed: lattice parameter a	3.684 Å	β alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 47 report
Lattice a printed: lattice parameter a	4.214 Å	γ-TiH alloy: Ti 0.5	model	[3] Ukita 2007	Table 2, p. 5, row 1 report
Lattice a printed: lattice parameter a	4.445 Å	δ-TiH2 alloy: Ti 0.333333	model	[3] Ukita 2007	Table 2, p. 5, row 2 report
Lattice a printed: lattice parameter a	3.202 Å	ε-TiH2 alloy: Ti 0.333333	model	[3] Ukita 2007	Table 2, p. 5, row 3 report
Lattice b printed: lattice parameter b	14.91 Å	α alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 39 report
Lattice b printed: lattice parameter b	15.643 Å	α alloy: H 0.25, Ti 0.75	DFT	[3] Ukita 2007	Table 1, p. 4, row 36 report
Lattice b printed: lattice parameter b	3.241 Å	β alloy: H 0.8, Ti 0.2	DFT	[3] Ukita 2007	Table 1, p. 4, row 50 report
Lattice b printed: lattice parameter b	5.368 Å	β alloy: H 0.75, Ti 0.25	DFT	[3] Ukita 2007	Table 1, p. 4, row 49 report
Lattice b printed: lattice parameter b	4.551 Å	β alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 47 report
Lattice b printed: lattice parameter b	3.234 Å	β alloy: H 0.333, Ti 0.667	DFT	[3] Ukita 2007	Table 1, p. 4, row 46 report
Lattice b printed: b	4.214 Å	γ-TiH alloy: Ti 0.5	model	[3] Ukita 2007	Table 2, p. 5, row 1 report
Lattice b printed: b	4.445 Å	δ-TiH2 alloy: Ti 0.333333	model	[3] Ukita 2007	Table 2, p. 5, row 2 report
Lattice b printed: b	3.202 Å	ε-TiH2 alloy: Ti 0.333333	model	[3] Ukita 2007	Table 2, p. 5, row 3 report
Lattice c printed: lattice parameter c	4.897 Å	α alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 39 report
Lattice c printed: lattice parameter c	5.961 Å	α alloy: H 0.667, Ti 0.333	DFT	[3] Ukita 2007	Table 1, p. 4, row 44 report
Lattice c printed: lattice parameter c	4.663 Å	α alloy: H 0.25, Ti 0.75	DFT	[3] Ukita 2007	Table 1, p. 4, row 36 report
Lattice c printed: lattice parameter c	3.153 Å	β alloy: H 0.8, Ti 0.2	DFT	[3] Ukita 2007	Table 1, p. 4, row 50 report
Lattice c printed: lattice parameter c	5.507 Å	β alloy: H 0.75, Ti 0.25	DFT	[3] Ukita 2007	Table 1, p. 4, row 49 report
Lattice c printed: lattice parameter c	4.039 Å	β alloy: H 0.667, Ti 0.333	DFT	[3] Ukita 2007	Table 1, p. 4, row 48 report
Lattice c printed: lattice parameter c	4.643 Å	β alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 47 report
Lattice c printed: c	4.602 Å	γ-TiH alloy: Ti 0.5	model	[3] Ukita 2007	Table 2, p. 5, row 1 report
Lattice c printed: c	4.445 Å	δ-TiH2 alloy: Ti 0.333333	model	[3] Ukita 2007	Table 2, p. 5, row 2 report
Lattice c printed: c	4.279 Å	ε-TiH2 alloy: Ti 0.333333	model	[3] Ukita 2007	Table 2, p. 5, row 3 report
lattice unspecified axis printed: α	90 °	α alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 39 report
lattice unspecified axis printed: γ	120 °	α alloy: H 0.667, Ti 0.333	DFT	[3] Ukita 2007	Table 1, p. 4, row 44 report
lattice unspecified axis printed: lattice parameter a=b	2.927 Å	α alloy: H 0.667, Ti 0.333	DFT	[3] Ukita 2007	Table 1, p. 4, row 44 report
lattice unspecified axis printed: α	90 °	α alloy: H 0.667, Ti 0.333	DFT	[3] Ukita 2007	Table 1, p. 4, row 44 report
lattice unspecified axis printed: α	90 °	α alloy: H 0.25, Ti 0.75	DFT	[3] Ukita 2007	Table 1, p. 4, row 36 report
lattice unspecified axis printed: γ	76.96 °	β alloy: H 0.8, Ti 0.2	DFT	[3] Ukita 2007	Table 1, p. 4, row 50 report
lattice unspecified axis printed: α	118.76 °	β alloy: H 0.8, Ti 0.2	DFT	[3] Ukita 2007	Table 1, p. 4, row 50 report
lattice unspecified axis printed: β	90.57 °	β alloy: H 0.8, Ti 0.2	DFT	[3] Ukita 2007	Table 1, p. 4, row 50 report
lattice unspecified axis printed: α	90 °	β alloy: H 0.75, Ti 0.25	DFT	[3] Ukita 2007	Table 1, p. 4, row 49 report
lattice unspecified axis printed: lattice parameter a=b	3.232 Å	β alloy: H 0.667, Ti 0.333	DFT	[3] Ukita 2007	Table 1, p. 4, row 48 report
lattice unspecified axis printed: α	90 °	β alloy: H 0.667, Ti 0.333	DFT	[3] Ukita 2007	Table 1, p. 4, row 48 report
lattice unspecified axis printed: α	90 °	β alloy: H 0.5, Ti 0.5	DFT	[3] Ukita 2007	Table 1, p. 4, row 47 report
lattice unspecified axis printed: lattice parameter a=c	4.763 Å	β alloy: H 0.333, Ti 0.667	DFT	[3] Ukita 2007	Table 1, p. 4, row 46 report
lattice unspecified axis printed: α	90 °	β alloy: H 0.333, Ti 0.667	DFT	[3] Ukita 2007	Table 1, p. 4, row 46 report
lattice unspecified axis printed: β	95.1 °	β alloy: H 0.333, Ti 0.667	DFT	[3] Ukita 2007	Table 1, p. 4, row 46 report

Sources

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

Kun Wang, Xiangcheng Kong, Junlin Du, Chonghe Li, Zhilin Li, Zhu Wu, Thermodynamic description of the Ti–H system, Calphad 34, 317-323 (2010). doi:10.1016/j.calphad.2010.07.001
E. Königsberger, G. Eriksson, W.A. Oates, Optimisation of the thermodynamic properties of the Ti–H and Zr–H systems, Journal of Alloys and Compounds 299, 148-152 (2000). doi:10.1016/s0925-8388(99)00816-6
Shusuke Ukita, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of the Ti-H and Zr-H Binary Phase Diagrams, J. Japan Inst. Metals 71, 721-729 (2007). doi:10.2320/jinstmet.71.721

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}
}