H–La phases

6 phases (tier A 3, tier C 1, liquid 1, gas 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–La system page · Markdown · field reference

Phases of the H–La system (6)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:h-la:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 1052.65–1382.5 K, x(H) 0–0.48649	0	1
DHCP phase:h-la:dhcp-a3	alpha-La · A3' · hP4 · P6_3/mmc (194)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1164.99 K, x(H) 0–0	0	1
FCC_A1 phase:h-la:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 532.94–1164.99 K, x(H) 0–0.20935	0	1
GAS phase:h-la:gas	gas	gas	stable in 1 of 1 calculated diagram(s): 300–2500 K, x(H) 0.99977–1	0	1
LAH2 phase:h-la:lah2	CeH3 · cF44 · Fm-3m (225)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1363.04 K, x(H) 0.64536–0.74999	4	1
LIQUID phase:h-la:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1193.01–2500 K, x(H) 0–0.45272	0	1

BCC_A2 (H–La)

Id: phase:h-la: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 1 of 1 calculated diagram(s): 1052.65–1382.5 K, x(H) 0–0.48649
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:h-la:bcc-a2
tdb: tdb:LaH-09Pal.tdb:BCC_A2

TDB models of BCC_A2 (1): PHASE and CONSTITUENT statements as written

LaH-09Pal.tdb: BCC_A2, type code %B, sha256 bb8224faf2d8e5ac…

35: PHASE BCC_A2 %B 2 1 3 !
36: CONST BCC_A2 : LA : H VA% : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2008.09.003 M. Palumbo, J. Urgnani, D. Baldissin, L. Battezzati, M. Baricco, Thermodynamic assessment of the H–La–Ni system, Calphad 33, 162-169 (2009).
assessment that models this phase

DHCP (H–La)

Id: phase:h-la:dhcp-a3; status assigned
Structure: alpha-La · A3' · hP4 · P6_3/mmc (194); type st:a3-alpha-la-hp4; tier A: standard phase name; confidence high
Stoichiometry: La 1.0000
Stability: stable in 1 of 1 calculated diagram(s): 300–1164.99 K, x(H) 0–0
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:h-la:dhcp-a3
tdb: tdb:LaH-09Pal.tdb:DHCP

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

LaH-09Pal.tdb: DHCP, type code %, sha256 bb8224faf2d8e5ac…

40: PHASE DHCP % 1 1 !
41: CONST DHCP : LA : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2008.09.003 M. Palumbo, J. Urgnani, D. Baldissin, L. Battezzati, M. Baricco, Thermodynamic assessment of the H–La–Ni system, Calphad 33, 162-169 (2009).
assessment that models this phase

FCC_A1 (H–La)

Id: phase:h-la:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; tier A: standard phase name; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 532.94–1164.99 K, x(H) 0–0.20935
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:h-la:fcc-a1
tdb: tdb:LaH-09Pal.tdb:FCC_A1

TDB models of FCC_A1 (1): PHASE and CONSTITUENT statements as written

LaH-09Pal.tdb: FCC_A1, type code %A, sha256 bb8224faf2d8e5ac…

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

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2008.09.003 M. Palumbo, J. Urgnani, D. Baldissin, L. Battezzati, M. Baricco, Thermodynamic assessment of the H–La–Ni system, Calphad 33, 162-169 (2009).
assessment that models this phase

GAS (H–La)

Id: phase:h-la:gas; status assigned
Structure: gas; type st:gas; gas; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–2500 K, x(H) 0.99977–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:h-la:gas
tdb: tdb:LaH-09Pal.tdb:GAS

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

LaH-09Pal.tdb: GAS, type code %, sha256 bb8224faf2d8e5ac…

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

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2008.09.003 M. Palumbo, J. Urgnani, D. Baldissin, L. Battezzati, M. Baricco, Thermodynamic assessment of the H–La–Ni system, Calphad 33, 162-169 (2009).
assessment that models this phase

LAH2 (H–La)

Id: phase:h-la:lah2; status assigned
Structure: CeH3 · cF44 · Fm-3m (225); type st:ceh3-cf44; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) doi:10.1016/j.calphad.2025.102833
Caveat: not certain from the name or DFT alone (no_structure_token, off_stoichiometric_model); structure as stated in the SGTE crystallographic table for this phase name and system
Stability: stable in 1 of 1 calculated diagram(s): 300–1363.04 K, x(H) 0.64536–0.74999
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:h-la:lah2
paper: paper:10.1016/j.calphad.2008.09.003:LaH2
tdb: tdb:LaH-09Pal.tdb:LAH2

TDB models of LAH2 (1): PHASE and CONSTITUENT statements as written

LaH-09Pal.tdb: LAH2, type code %, sha256 bb8224faf2d8e5ac…

46: PHASE LAH2 % 3 1 2 1 !
47: CONST LAH2 : LA : H VA : H VA : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2008.09.003 M. Palumbo, J. Urgnani, D. Baldissin, L. Battezzati, M. Baricco, Thermodynamic assessment of the H–La–Ni system, Calphad 33, 162-169 (2009).
assessment that models this phase; reports values for this phase

LIQUID (H–La)

Id: phase:h-la:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1193.01–2500 K, x(H) 0–0.45272
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:h-la:liquid
tdb: tdb:LaH-09Pal.tdb:LIQUID

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

LaH-09Pal.tdb: LIQUID, type code %, sha256 bb8224faf2d8e5ac…

25: PHASE LIQUID:L % 1 1 !
26: CONST LIQUID:L : H LA : !

Example references (1 of 1; assessments first):

doi:10.1016/j.calphad.2008.09.003 M. Palumbo, J. Urgnani, D. Baldissin, L. Battezzati, M. Baricco, Thermodynamic assessment of the H–La–Ni system, Calphad 33, 162-169 (2009).
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}
}