H–Ti phases

7 phases (tier A 3, liquid 1, gas 1, needs_review 1, interstitial_fcc_a1_compound 1); 7 stable in a calculated diagram. Structure types are assigned only when the stored evidence supports an assignment under the stated tier rules (tier A: standard phase name; tier B: unique Materials Project + OQMD on-hull match, DFT-supported; tier C: one structure stated by the assessment's crystallographic table, assessor-stated); other phases list candidates and are marked needs_review. Stability is from phase diagrams calculated with pycalphad from the SGTE binary collection (evidence class: model).

Data: interactive registry · full JSON · H–Ti system page · Markdown · field reference

Phases of the H–Ti system (7)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:h-ti:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 5 of 5 calculated diagram(s): 561.33–2259.99 K, x(H) 0–0.52817	8	5
FCC_A1 phase:h-ti:fcc-a1	CaF2 · C1 · cF12 · Fm-3m (225)	assigned	stable in 5 of 5 calculated diagram(s): 300–948.24 K, x(H) 0.50248–0.66667	0	5
GAS phase:h-ti:gas	gas	gas	stable in 5 of 5 calculated diagram(s): 300–2500 K, x(H) 1–1	0	5
HCP_A3 phase:h-ti:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	stable in 5 of 5 calculated diagram(s): 300–2259.99 K, x(H) 0–0.10002	6	5
LIQUID phase:h-ti:liquid	liquid	liquid	stable in 5 of 5 calculated diagram(s): 1486–2500 K, x(H) 0–0.09203	5	5
TIH_B17 phase:h-ti:tih-b17	PtS · B17 · tP4 · P4_2/mmc (131)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–440.98 K, x(H) 0.5–0.5	0	1
TIH2_L2B phase:h-ti:tih2-l2b		needs_review	stable in 1 of 1 calculated diagram(s): 300–333.32 K, x(H) 0.66667–0.66667	0	1

BCC_A2 (H–Ti)

Id: phase:h-ti:bcc-a2; status assigned
Structure: W · A2 · cI2 · Im-3m (229); type st:a2-w-ci2; tier A: standard phase name; confidence high
Stability: stable in 5 of 5 calculated diagram(s): 561.33–2259.99 K, x(H) 0–0.52817
Literature: 8 values (8 accepted) from 1 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:h-ti:bcc-a2
paper: paper:10.1016/j.calphad.2010.07.001:β
tdb: tdb:TiH-00Koe.tdb:BCC_A2, tdb:TiH-07Uki.tdb:BCC_A2, tdb:TiH-08Qiu.tdb:BCC_A2, tdb:TiH-10Wan.tdb:BCC_A2, tdb:TiH-87Kiv.tdb:BCC_A2

TDB models of BCC_A2 (5): PHASE and CONSTITUENT statements as written

TiH-00Koe.tdb: BCC_A2, type code %B, sha256 f6ece47290a9e8df…

36: PHASE BCC_A2 %B 2 1 1.5 !
37: CONST BCC_A2 : TI : H VA% : !

TiH-07Uki.tdb: BCC_A2, type code %B, sha256 9f0b5aca2ec52585…

35: PHASE BCC_A2 %B 2 1 6 !
36: CONST BCC_A2 : TI : H VA% : !

TiH-08Qiu.tdb: BCC_A2, type code %B, sha256 dc2ff19793b3ae2f…

37: PHASE BCC_A2 %B 2 1 3 !
38: CONST BCC_A2 : TI : H VA% : !

TiH-10Wan.tdb: BCC_A2, type code %B, sha256 4d284f0864b71b93…

39: PHASE BCC_A2 %B 2 1 1.5 !
40: CONST BCC_A2 : TI : H VA% : !

TiH-87Kiv.tdb: BCC_A2, type code %B, sha256 0ea0e065649731f5…

39: PHASE BCC_A2 %B 2 1 3 !
40: CONST BCC_A2 : TI : H VA% : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2010.07.001 Kun Wang, Xiangcheng Kong, Junlin Du, Chonghe Li, Zhilin Li, Zhu Wu, Thermodynamic description of the Ti–H system, Calphad 34, 317-323 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/0364-5916(87)90014-9 J.K. Kivilahti, J.M. Miettinen, A thermodynamic analysis of the ti-h system, Calphad 11, 187-199 (1987).
assessment that models this phase; cited as the source of values for this phase
doi:10.1016/j.calphad.2008.08.005 Caian Qiu, Susanne M. Opalka, Ole M. Løvvik, Gregory B. Olson, Thermodynamic modeling of the Na–Al–Ti–H system and Ti dissolution in sodium alanates, Calphad 32, 624-636 (2008).
assessment that models this phase
doi:10.2320/jinstmet.71.721 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).
assessment that models this phase

FCC_A1 (H–Ti)

Id: phase:h-ti:fcc-a1; status assigned
Structure: CaF2 · C1 · cF12 · Fm-3m (225); type st:c1-caf2-cf12; interstitial_fcc_a1_compound; confidence high
Stability: stable in 5 of 5 calculated diagram(s): 300–948.24 K, x(H) 0.50248–0.66667
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:h-ti:fcc-a1
tdb: tdb:TiH-00Koe.tdb:FCC_A1, tdb:TiH-07Uki.tdb:FCC_A1, tdb:TiH-08Qiu.tdb:FCC_A1, tdb:TiH-10Wan.tdb:FCC_A1, tdb:TiH-87Kiv.tdb:FCC_A1

TDB models of FCC_A1 (5): PHASE and CONSTITUENT statements as written

TiH-00Koe.tdb: FCC_A1, type code %A, sha256 f6ece47290a9e8df…

31: PHASE FCC_A1 %A 2 1 2 !
32: CONST FCC_A1 : TI : H% VA : !

TiH-07Uki.tdb: FCC_A1, type code %A, sha256 9f0b5aca2ec52585…

30: PHASE FCC_A1 %A 2 1 2 !
31: CONST FCC_A1 : TI : H% VA : !

TiH-08Qiu.tdb: FCC_A1, type code %A, sha256 dc2ff19793b3ae2f…

32: PHASE FCC_A1 %A 2 1 2 !
33: CONST FCC_A1 : TI : H% VA : !

TiH-10Wan.tdb: FCC_A1, type code %A, sha256 4d284f0864b71b93…

34: PHASE FCC_A1 %A 2 1 2 !
35: CONST FCC_A1 : TI : H% VA : !

TiH-87Kiv.tdb: FCC_A1, type code %A, sha256 0ea0e065649731f5…

34: PHASE FCC_A1 %A 2 1 2 !
35: CONST FCC_A1 : TI : H% VA : !

Example references (4 of 4; assessments first):

doi:10.1016/0364-5916(87)90014-9 J.K. Kivilahti, J.M. Miettinen, A thermodynamic analysis of the ti-h system, Calphad 11, 187-199 (1987).
assessment that models this phase
doi:10.1016/j.calphad.2008.08.005 Caian Qiu, Susanne M. Opalka, Ole M. Løvvik, Gregory B. Olson, Thermodynamic modeling of the Na–Al–Ti–H system and Ti dissolution in sodium alanates, Calphad 32, 624-636 (2008).
assessment that models this phase
doi:10.1016/j.calphad.2010.07.001 Kun Wang, Xiangcheng Kong, Junlin Du, Chonghe Li, Zhilin Li, Zhu Wu, Thermodynamic description of the Ti–H system, Calphad 34, 317-323 (2010).
assessment that models this phase
doi:10.2320/jinstmet.71.721 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).
assessment that models this phase

GAS (H–Ti)

Id: phase:h-ti:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 5 of 5 calculated diagram(s): 300–2500 K, x(H) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:h-ti:gas
tdb: tdb:TiH-00Koe.tdb:GAS, tdb:TiH-07Uki.tdb:GAS, tdb:TiH-08Qiu.tdb:GAS, tdb:TiH-10Wan.tdb:GAS, tdb:TiH-87Kiv.tdb:GAS

TDB models of GAS (5): PHASE and CONSTITUENT statements as written

TiH-00Koe.tdb: GAS, type code %, sha256 f6ece47290a9e8df…

44: PHASE GAS:G % 1 1 !
45: CONST GAS:G : H H2 : !

TiH-07Uki.tdb: GAS, type code %, sha256 9f0b5aca2ec52585…

53: PHASE GAS:G % 1 1 !
54: CONST GAS:G : H H2 : !

TiH-08Qiu.tdb: GAS, type code %, sha256 dc2ff19793b3ae2f…

45: PHASE GAS:G % 1 1 !
46: CONST GAS:G : H H2 : !

TiH-10Wan.tdb: GAS, type code %, sha256 4d284f0864b71b93…

47: PHASE GAS:G % 1 1 !
48: CONST GAS:G : H H2 : !

TiH-87Kiv.tdb: GAS, type code %, sha256 0ea0e065649731f5…

47: PHASE GAS:G % 1 1 !
48: CONST GAS:G : H H2 : !

Example references (4 of 4; assessments first):

doi:10.1016/0364-5916(87)90014-9 J.K. Kivilahti, J.M. Miettinen, A thermodynamic analysis of the ti-h system, Calphad 11, 187-199 (1987).
assessment that models this phase
doi:10.1016/j.calphad.2008.08.005 Caian Qiu, Susanne M. Opalka, Ole M. Løvvik, Gregory B. Olson, Thermodynamic modeling of the Na–Al–Ti–H system and Ti dissolution in sodium alanates, Calphad 32, 624-636 (2008).
assessment that models this phase
doi:10.1016/j.calphad.2010.07.001 Kun Wang, Xiangcheng Kong, Junlin Du, Chonghe Li, Zhilin Li, Zhu Wu, Thermodynamic description of the Ti–H system, Calphad 34, 317-323 (2010).
assessment that models this phase
doi:10.2320/jinstmet.71.721 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).
assessment that models this phase

HCP_A3 (H–Ti)

Id: phase:h-ti:hcp-a3; status assigned
Structure: Mg · A3 · hP2 · P6_3/mmc (194); type st:a3-mg-hp2; tier A: standard phase name; confidence high
Stability: stable in 5 of 5 calculated diagram(s): 300–2259.99 K, x(H) 0–0.10002
Literature: 6 values (6 accepted) from 1 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:h-ti:hcp-a3
paper: paper:10.1016/j.calphad.2010.07.001:α
tdb: tdb:TiH-00Koe.tdb:HCP_A3, tdb:TiH-07Uki.tdb:HCP_A3, tdb:TiH-08Qiu.tdb:HCP_A3, tdb:TiH-10Wan.tdb:HCP_A3, tdb:TiH-87Kiv.tdb:HCP_A3

TDB models of HCP_A3 (5): PHASE and CONSTITUENT statements as written

TiH-00Koe.tdb: HCP_A3, type code %A, sha256 f6ece47290a9e8df…

41: PHASE HCP_A3 %A 2 1 1 !
42: CONST HCP_A3 : TI : H VA% : !

TiH-07Uki.tdb: HCP_A3, type code %A, sha256 9f0b5aca2ec52585…

40: PHASE HCP_A3 %A 2 1 2 !
41: CONST HCP_A3 : TI : H VA% : !

TiH-08Qiu.tdb: HCP_A3, type code %A, sha256 dc2ff19793b3ae2f…

42: PHASE HCP_A3 %A 2 1 0.5 !
43: CONST HCP_A3 : TI : H VA% : !

TiH-10Wan.tdb: HCP_A3, type code %A, sha256 4d284f0864b71b93…

44: PHASE HCP_A3 %A 2 1 0.5 !
45: CONST HCP_A3 : TI : H VA% : !

TiH-87Kiv.tdb: HCP_A3, type code %A, sha256 0ea0e065649731f5…

44: PHASE HCP_A3 %A 2 1 1 !
45: CONST HCP_A3 : TI : H VA% : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2010.07.001 Kun Wang, Xiangcheng Kong, Junlin Du, Chonghe Li, Zhilin Li, Zhu Wu, Thermodynamic description of the Ti–H system, Calphad 34, 317-323 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/0364-5916(87)90014-9 J.K. Kivilahti, J.M. Miettinen, A thermodynamic analysis of the ti-h system, Calphad 11, 187-199 (1987).
assessment that models this phase; cited as the source of values for this phase
doi:10.1016/j.calphad.2008.08.005 Caian Qiu, Susanne M. Opalka, Ole M. Løvvik, Gregory B. Olson, Thermodynamic modeling of the Na–Al–Ti–H system and Ti dissolution in sodium alanates, Calphad 32, 624-636 (2008).
assessment that models this phase
doi:10.2320/jinstmet.71.721 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).
assessment that models this phase

LIQUID (H–Ti)

Id: phase:h-ti:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 5 of 5 calculated diagram(s): 1486–2500 K, x(H) 0–0.09203
Literature: 5 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (8): corpus: corpus:phase:h-ti:liquid
paper: paper:10.1016/j.calphad.2010.07.001:L1, paper:10.1016/j.calphad.2010.07.001:liquid
tdb: tdb:TiH-00Koe.tdb:LIQUID, tdb:TiH-07Uki.tdb:LIQUID, tdb:TiH-08Qiu.tdb:LIQUID, tdb:TiH-10Wan.tdb:LIQUID, tdb:TiH-87Kiv.tdb:LIQUID

TDB models of LIQUID (5): PHASE and CONSTITUENT statements as written

TiH-00Koe.tdb: LIQUID, type code %, sha256 f6ece47290a9e8df…

26: PHASE LIQUID:L % 1 1 !
27: CONST LIQUID:L : TI : !

TiH-07Uki.tdb: LIQUID, type code %, sha256 9f0b5aca2ec52585…

25: PHASE LIQUID:L % 1 1 !
26: CONST LIQUID:L : TI : !

TiH-08Qiu.tdb: LIQUID, type code %, sha256 dc2ff19793b3ae2f…

27: PHASE LIQUID:L % 1 1 !
28: CONST LIQUID:L : H TI : !

TiH-10Wan.tdb: LIQUID, type code %, sha256 4d284f0864b71b93…

29: PHASE LIQUID:L % 1 1 !
30: CONST LIQUID:L : H TI TIH2 : !

TiH-87Kiv.tdb: LIQUID, type code %, sha256 0ea0e065649731f5…

29: PHASE LIQUID:L % 1 1 !
30: CONST LIQUID:L : TI : !

Example references (4 of 4; assessments first):

doi:10.1016/j.calphad.2010.07.001 Kun Wang, Xiangcheng Kong, Junlin Du, Chonghe Li, Zhilin Li, Zhu Wu, Thermodynamic description of the Ti–H system, Calphad 34, 317-323 (2010).
assessment that models this phase; reports values for this phase
doi:10.1016/0364-5916(87)90014-9 J.K. Kivilahti, J.M. Miettinen, A thermodynamic analysis of the ti-h system, Calphad 11, 187-199 (1987).
assessment that models this phase
doi:10.1016/j.calphad.2008.08.005 Caian Qiu, Susanne M. Opalka, Ole M. Løvvik, Gregory B. Olson, Thermodynamic modeling of the Na–Al–Ti–H system and Ti dissolution in sodium alanates, Calphad 32, 624-636 (2008).
assessment that models this phase
doi:10.2320/jinstmet.71.721 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).
assessment that models this phase

TIH_B17 (H–Ti)

Id: phase:h-ti:tih-b17; status assigned
Structure: PtS · B17 · tP4 · P4_2/mmc (131); type st:b17-pts-tp4; tier A: standard phase name; confidence high
Stoichiometry: H 0.5000, Ti 0.5000
Stability: stable in 1 of 1 calculated diagram(s): 300–440.98 K, x(H) 0.5–0.5
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:h-ti:tih-b17
tdb: tdb:TiH-07Uki.tdb:TIH_B17

TDB models of TIH_B17 (1): PHASE and CONSTITUENT statements as written

TiH-07Uki.tdb: TIH_B17, type code %, sha256 9f0b5aca2ec52585…

45: PHASE TIH_B17 % 2 1 1 !
46: CONST TIH_B17 : TI : H : !

Example references (1 of 1; assessments first):

doi:10.2320/jinstmet.71.721 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).
assessment that models this phase

TIH2_L2B (H–Ti)

Id: phase:h-ti:tih2-l2b; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:L2B; no_structure_token
Candidate (sgte_mmc2): ThH2 · L'2_b · tI6 · I4/mmm (139) — Hallstedt 2025 mmc2 row for TIH2_L2B: TiH2-epsilon
Candidate (tdb_comment): ThH2 · tI6 · I4/mmm — TiH-07Uki.tdb: 'Prototype ThH2 (tI6, I4/mmm), epsilon'
Stability: stable in 1 of 1 calculated diagram(s): 300–333.32 K, x(H) 0.66667–0.66667
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:h-ti:tih2-l2b
tdb: tdb:TiH-07Uki.tdb:TIH2_L2B

TDB models of TIH2_L2B (1): PHASE and CONSTITUENT statements as written

TiH-07Uki.tdb: TIH2_L2B, type code %, sha256 9f0b5aca2ec52585…

50: PHASE TIH2_L2B % 2 1 2 !
51: CONST TIH2_L2B : TI : H% VA : !

Example references (1 of 1; assessments first):

doi:10.2320/jinstmet.71.721 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).
assessment that models this phase

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Registry: phase registry of binary systems (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735970
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 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; 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); the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work). 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_phase_registry_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Registry: phase registry of binary systems}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735970},
  url       = {https://doi.org/10.5281/zenodo.23735970},
  note      = {Version 1, machine-extracted}
}

@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}
}