H–Y phases

6 phases (tier A 1, liquid 1, gas 2, needs_review 1, interstitial_fcc_a1_compound 1); 6 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–Y system page · Markdown · field reference

Phases of the H–Y system (6)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:h-y:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 397.65–1795.28 K, x(H) 0–6e-05	0	2
FCC_A1 phase:h-y:fcc-a1	CaF2 · C1 · cF12 · Fm-3m (225)	assigned	stable in 2 of 2 calculated diagram(s): 300–1721.6 K, x(H) 0.47001–0.67677	10	2
GAS phase:h-y:gas	gas	gas	stable in 2 of 2 calculated diagram(s): 300.62–2500 K, x(H) 0.99795–1	8	2
H2GAS phase:h-y:h2gas	gas	gas	stable in 2 of 2 calculated diagram(s): 300–1092.08 K, x(H) 1–1	2	2
HCP_A3 phase:h-y:hcp-a3		needs_review	stable in 2 of 2 calculated diagram(s): 300–2303.37 K, x(H) 0–0.74997	12	2
LIQUID phase:h-y:liquid	liquid	liquid	stable in 2 of 2 calculated diagram(s): 397.65–2500 K, x(H) 0–0	0	2

BCC_A2 (H–Y)

Id: phase:h-y: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 2 of 2 calculated diagram(s): 397.65–1795.28 K, x(H) 0–6e-05
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:h-y:bcc-a2
tdb: tdb:YH-18Fu.tdb:BCC_A2, tdb:YH-20Pen.tdb:BCC_A2

TDB models of BCC_A2 (2): PHASE and CONSTITUENT statements as written

YH-18Fu.tdb: BCC_A2, type code %B, sha256 32726376eb96be71…

41: PHASE BCC_A2 %B 2 1 1 !
42: CONST BCC_A2 : Y : H VA% : !

YH-20Pen.tdb: BCC_A2, type code %B, sha256 d8a7b7aea58fca94…

38: PHASE BCC_A2 %B 2 1 1 !
39: CONST BCC_A2 : Y : H VA% : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2020.152035 Jiaqing Peng, Ming Wu, Fu Du, Fengli Yang, Jianyun Shen, Lijun Wang et al., Thermodynamic modelling of Y–H and Y–Zr–H system aided by first-principles and its application in bulk hydride moderator fabrication, Journal of Nuclear Materials 531, 152035 (2020).
assessment that models this phase
doi:10.1016/j.pnsc.2018.04.001 Kai Fu, Xiaojing Jiang, Yanru Guo, Shuan Li, Jie Zheng, Wenhuai Tian et al., Experimental investigation and thermodynamic assessment of the yttrium-hydrogen binary system, Progress in Natural Science: Materials International 28, 332-336 (2018).
assessment that models this phase

FCC_A1 (H–Y)

Id: phase:h-y: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 2 of 2 calculated diagram(s): 300–1721.6 K, x(H) 0.47001–0.67677
Literature: 10 values (10 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:h-y:fcc-a1
paper: paper:10.1016/j.jnucmat.2020.152035:fcc
tdb: tdb:YH-18Fu.tdb:FCC_A1, tdb:YH-20Pen.tdb:FCC_A1

TDB models of FCC_A1 (2): PHASE and CONSTITUENT statements as written

YH-18Fu.tdb: FCC_A1, type code %A, sha256 32726376eb96be71…

36: PHASE FCC_A1 %A 3 1 1 2 !
37: CONST FCC_A1 : Y : H VA% : H% VA : !

YH-20Pen.tdb: FCC_A1, type code %A, sha256 d8a7b7aea58fca94…

33: PHASE FCC_A1 %A 3 1 1 2 !
34: CONST FCC_A1 : Y : H VA% : H% VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2020.152035 Jiaqing Peng, Ming Wu, Fu Du, Fengli Yang, Jianyun Shen, Lijun Wang et al., Thermodynamic modelling of Y–H and Y–Zr–H system aided by first-principles and its application in bulk hydride moderator fabrication, Journal of Nuclear Materials 531, 152035 (2020).
assessment that models this phase; reports values for this phase
doi:10.1016/j.pnsc.2018.04.001 Kai Fu, Xiaojing Jiang, Yanru Guo, Shuan Li, Jie Zheng, Wenhuai Tian et al., Experimental investigation and thermodynamic assessment of the yttrium-hydrogen binary system, Progress in Natural Science: Materials International 28, 332-336 (2018).
assessment that models this phase

GAS (H–Y)

Id: phase:h-y:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300.62–2500 K, x(H) 0.99795–1
Literature: 8 values (8 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:h-y:gas
paper: paper:10.1016/j.jnucmat.2020.152035:GAS(H2)
tdb: tdb:YH-18Fu.tdb:GAS, tdb:YH-20Pen.tdb:GAS

TDB models of GAS (2): PHASE and CONSTITUENT statements as written

YH-18Fu.tdb: GAS, type code %, sha256 32726376eb96be71…

49: PHASE GAS:G % 1 1 !
50: CONST GAS:G : H H2 Y : !

YH-20Pen.tdb: GAS, type code %, sha256 d8a7b7aea58fca94…

46: PHASE GAS:G % 1 1 !
47: CONST GAS:G : H H2 Y : !

Example references (4 of 4; assessments first):

doi:10.1016/j.jnucmat.2020.152035 Jiaqing Peng, Ming Wu, Fu Du, Fengli Yang, Jianyun Shen, Lijun Wang et al., Thermodynamic modelling of Y–H and Y–Zr–H system aided by first-principles and its application in bulk hydride moderator fabrication, Journal of Nuclear Materials 531, 152035 (2020).
assessment that models this phase; reports values for this phase
doi:10.1016/j.pnsc.2018.04.001 Kai Fu, Xiaojing Jiang, Yanru Guo, Shuan Li, Jie Zheng, Wenhuai Tian et al., Experimental investigation and thermodynamic assessment of the yttrium-hydrogen binary system, Progress in Natural Science: Materials International 28, 332-336 (2018).
assessment that models this phase; cited as the source of values for this phase
doi:10.1021/j100892a004 L. N. Yannopoulos, R. K. Edwards, P. G. Wahlbeck, The Thermodynamics of the Yttrium-Hydrogen System<sup>1</sup>, J. Phys. Chem. 69, 2510-2515 (1965).
cited as the source of values for this phase
doi:10.1149/1.2425565 C. E. Lundin, J. P. Blackledge, Pressure-Temperature-Composition Relationships of the Yttrium-Hydrogen System, J. Electrochem. Soc. 109, 838 (1962).
cited as the source of values for this phase

H2GAS (H–Y)

Id: phase:h-y:h2gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300–1092.08 K, x(H) 1–1
Literature: 2 values (2 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:h-y:h2gas
paper: paper:10.1016/j.pnsc.2018.04.001:Gas(H2)
tdb: tdb:YH-18Fu.tdb:H2GAS, tdb:YH-20Pen.tdb:H2GAS

TDB models of H2GAS (2): PHASE and CONSTITUENT statements as written

YH-18Fu.tdb: H2GAS, type code %, sha256 32726376eb96be71…

52: PHASE H2GAS % 1 1 !
53: CONST H2GAS : H2 : !

YH-20Pen.tdb: H2GAS, type code %, sha256 d8a7b7aea58fca94…

49: PHASE H2GAS % 1 1 !
50: CONST H2GAS : H2 : !

Example references (2 of 2; assessments first):

doi:10.1016/j.pnsc.2018.04.001 Kai Fu, Xiaojing Jiang, Yanru Guo, Shuan Li, Jie Zheng, Wenhuai Tian et al., Experimental investigation and thermodynamic assessment of the yttrium-hydrogen binary system, Progress in Natural Science: Materials International 28, 332-336 (2018).
assessment that models this phase; reports values for this phase
doi:10.1016/j.jnucmat.2020.152035 Jiaqing Peng, Ming Wu, Fu Du, Fengli Yang, Jianyun Shen, Lijun Wang et al., Thermodynamic modelling of Y–H and Y–Zr–H system aided by first-principles and its application in bulk hydride moderator fabrication, Journal of Nuclear Materials 531, 152035 (2020).
assessment that models this phase

HCP_A3 (H–Y)

Id: phase:h-y:hcp-a3; status needs_review
No structure assigned. Why: assessment_declared_blocked_by:sgte_mmc2_row_disagrees_with_name; sgte_mmc2_row_disagrees_with_name:HCP_A3
Candidate (literature_printed): HoH3 · hP24 — printed with a label mapped to this phase
Candidate (name_token): Mg · A3 · hP2 · P6_3/mmc (194) — Strukturbericht/word 'A3' in the TDB name
Candidate (sgte_mmc2): HoH3 · hP24 · P-3c1 (165) — Hallstedt 2025 mmc2 row for HCP_A3: DyH3, ErH3, GdH3, YH3
Stability: stable in 2 of 2 calculated diagram(s): 300–2303.37 K, x(H) 0–0.74997
Literature: 12 values (12 accepted) from 2 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:h-y:hcp-a3
paper: paper:10.1016/j.jnucmat.2020.152035:HCP(Y), paper:10.1016/j.jnucmat.2020.152035:hcp, paper:10.1016/j.pnsc.2018.04.001:α-Y
tdb: tdb:YH-18Fu.tdb:HCP_A3, tdb:YH-20Pen.tdb:HCP_A3

TDB models of HCP_A3 (2): PHASE and CONSTITUENT statements as written

YH-18Fu.tdb: HCP_A3, type code %A, sha256 32726376eb96be71…

46: PHASE HCP_A3 %A 3 1 1 2 !
47: CONST HCP_A3 : Y : H VA% : H VA% : !

YH-20Pen.tdb: HCP_A3, type code %A, sha256 d8a7b7aea58fca94…

43: PHASE HCP_A3 %A 3 1 1 2 !
44: CONST HCP_A3 : Y : H VA% : H VA% : !

Example references (3 of 3; assessments first):

doi:10.1016/j.jnucmat.2020.152035 Jiaqing Peng, Ming Wu, Fu Du, Fengli Yang, Jianyun Shen, Lijun Wang et al., Thermodynamic modelling of Y–H and Y–Zr–H system aided by first-principles and its application in bulk hydride moderator fabrication, Journal of Nuclear Materials 531, 152035 (2020).
assessment that models this phase; reports values for this phase
doi:10.1016/j.pnsc.2018.04.001 Kai Fu, Xiaojing Jiang, Yanru Guo, Shuan Li, Jie Zheng, Wenhuai Tian et al., Experimental investigation and thermodynamic assessment of the yttrium-hydrogen binary system, Progress in Natural Science: Materials International 28, 332-336 (2018).
assessment that models this phase; cited as the source of values for this phase; reports values for this phase
doi:10.1149/1.2425565 C. E. Lundin, J. P. Blackledge, Pressure-Temperature-Composition Relationships of the Yttrium-Hydrogen System, J. Electrochem. Soc. 109, 838 (1962).
cited as the source of values for this phase

LIQUID (H–Y)

Id: phase:h-y:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stoichiometry: Y 1.0000
Stability: stable in 2 of 2 calculated diagram(s): 397.65–2500 K, x(H) 0–0
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:h-y:liquid
tdb: tdb:YH-18Fu.tdb:LIQUID, tdb:YH-20Pen.tdb:LIQUID

TDB models of LIQUID (2): PHASE and CONSTITUENT statements as written

YH-18Fu.tdb: LIQUID, type code %, sha256 32726376eb96be71…

31: PHASE LIQUID:L % 1 1 !
32: CONST LIQUID:L : Y : !

YH-20Pen.tdb: LIQUID, type code %, sha256 d8a7b7aea58fca94…

28: PHASE LIQUID:L % 1 1 !
29: CONST LIQUID:L : Y : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jnucmat.2020.152035 Jiaqing Peng, Ming Wu, Fu Du, Fengli Yang, Jianyun Shen, Lijun Wang et al., Thermodynamic modelling of Y–H and Y–Zr–H system aided by first-principles and its application in bulk hydride moderator fabrication, Journal of Nuclear Materials 531, 152035 (2020).
assessment that models this phase
doi:10.1016/j.pnsc.2018.04.001 Kai Fu, Xiaojing Jiang, Yanru Guo, Shuan Li, Jie Zheng, Wenhuai Tian et al., Experimental investigation and thermodynamic assessment of the yttrium-hydrogen binary system, Progress in Natural Science: Materials International 28, 332-336 (2018).
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}
}