Am–Np phases

7 phases (tier A 6, liquid 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 · Am–Np system page · Markdown · field reference

Phases of the Am–Np system (7)
Phase	Structure	Basis	Stability (calculated)	TDB models
TETRAG_AD phase:am-np:ad-tetrag	beta-Np · A_d · tP4 · P4/nmm (129)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 555.03–910.95 K, x(Np) 0.99776–1	2
BCC_A2 phase:am-np:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 823.05–2499.34 K, x(Np) 0–1	2
DHCP phase:am-np:dhcp-a3	alpha-La · A3' · hP4 · P6_3/mmc (194)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–1362.47 K, x(Np) 0–0.00653	2
FCC_A1 phase:am-np:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 787.47–1362.47 K, x(Np) 0–0.13302	2
HCP_A3 phase:am-np:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 2 calculated diagram(s)	2
LIQUID phase:am-np:liquid	liquid	liquid	stable in 2 of 2 calculated diagram(s): 882.99–2500 K, x(Np) 0–1	2
ORTHO_AC phase:am-np:ortho-ac	alpha-Np · A_c · oP8 · Pnma (62)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–555.03 K, x(Np) 0.99991–1	2

TETRAG_AD (Am–Np)

Id: phase:am-np:ad-tetrag; status assigned
Structure: beta-Np · A_d · tP4 · P4/nmm (129); type st:a-d-beta-np-tp4; tier A: standard phase name; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 555.03–910.95 K, x(Np) 0.99776–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:am-np:ad-tetrag
tdb: tdb:AmNp-10Kur.tdb:TETRAG_AD, tdb:AmNp-93Oga.tdb:TETRAG_AD

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

AmNp-10Kur.tdb: TETRAG_AD, type code %, sha256 2a5ba036840cfb6c…

50: PHASE TETRAG_AD % 1 1 !
51: CONST TETRAG_AD : AM NP% : !

AmNp-93Oga.tdb: TETRAG_AD, type code %, sha256 cfa44b10057e67b3…

56: PHASE TETRAG_AD % 1 1 !
57: CONST TETRAG_AD : NP : !

Example references (1 of 1; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase

BCC_A2 (Am–Np)

Id: phase:am-np: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): 823.05–2499.34 K, x(Np) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:am-np:bcc-a2
tdb: tdb:AmNp-10Kur.tdb:BCC_A2, tdb:AmNp-93Oga.tdb:BCC_A2

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

AmNp-10Kur.tdb: BCC_A2, type code %B, sha256 2a5ba036840cfb6c…

30: PHASE BCC_A2 %B 2 1 3 !
31: CONST BCC_A2 : AM% NP% : VA : !

AmNp-93Oga.tdb: BCC_A2, type code %B, sha256 cfa44b10057e67b3…

36: PHASE BCC_A2 %B 2 1 3 !
37: CONST BCC_A2 : AM% NP% : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase

DHCP (Am–Np)

Id: phase:am-np: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
Stability: stable in 2 of 2 calculated diagram(s): 300–1362.47 K, x(Np) 0–0.00653
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:am-np:dhcp-a3
tdb: tdb:AmNp-10Kur.tdb:DHCP, tdb:AmNp-93Oga.tdb:DHCP

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

AmNp-10Kur.tdb: DHCP, type code %, sha256 2a5ba036840cfb6c…

40: PHASE DHCP % 1 1 !
41: CONST DHCP : AM% NP : !

AmNp-93Oga.tdb: DHCP, type code %, sha256 cfa44b10057e67b3…

46: PHASE DHCP % 1 1 !
47: CONST DHCP : AM : !

Example references (1 of 1; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase

FCC_A1 (Am–Np)

Id: phase:am-np: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 2 of 2 calculated diagram(s): 787.47–1362.47 K, x(Np) 0–0.13302
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:am-np:fcc-a1
tdb: tdb:AmNp-10Kur.tdb:FCC_A1, tdb:AmNp-93Oga.tdb:FCC_A1

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

AmNp-10Kur.tdb: FCC_A1, type code %A, sha256 2a5ba036840cfb6c…

25: PHASE FCC_A1 %A 2 1 1 !
26: CONST FCC_A1 : AM% NP : VA : !

AmNp-93Oga.tdb: FCC_A1, type code %A, sha256 cfa44b10057e67b3…

31: PHASE FCC_A1 %A 2 1 1 !
32: CONST FCC_A1 : AM% NP : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase

HCP_A3 (Am–Np)

Id: phase:am-np: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: not stable in 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:am-np:hcp-a3
tdb: tdb:AmNp-10Kur.tdb:HCP_A3, tdb:AmNp-93Oga.tdb:HCP_A3

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

AmNp-10Kur.tdb: HCP_A3, type code %A, sha256 2a5ba036840cfb6c…

35: PHASE HCP_A3 %A 2 1 0.5 !
36: CONST HCP_A3 : AM NP : VA : !

AmNp-93Oga.tdb: HCP_A3, type code %A, sha256 cfa44b10057e67b3…

41: PHASE HCP_A3 %A 2 1 0.5 !
42: CONST HCP_A3 : AM NP : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase

LIQUID (Am–Np)

Id: phase:am-np:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 882.99–2500 K, x(Np) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:am-np:liquid
tdb: tdb:AmNp-10Kur.tdb:LIQUID, tdb:AmNp-93Oga.tdb:LIQUID

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

AmNp-10Kur.tdb: LIQUID, type code %, sha256 2a5ba036840cfb6c…

20: PHASE LIQUID:L % 1 1 !
21: CONST LIQUID:L : AM NP : !

AmNp-93Oga.tdb: LIQUID, type code %, sha256 cfa44b10057e67b3…

26: PHASE LIQUID:L % 1 1 !
27: CONST LIQUID:L : AM NP : !

Example references (1 of 1; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
assessment that models this phase

ORTHO_AC (Am–Np)

Id: phase:am-np:ortho-ac; status assigned
Structure: alpha-Np · A_c · oP8 · Pnma (62); type st:a-c-alpha-np-op8; tier A: standard phase name; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 300–555.03 K, x(Np) 0.99991–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:am-np:ortho-ac
tdb: tdb:AmNp-10Kur.tdb:ORTHO_AC, tdb:AmNp-93Oga.tdb:ORTHO_AC

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

AmNp-10Kur.tdb: ORTHO_AC, type code %, sha256 2a5ba036840cfb6c…

45: PHASE ORTHO_AC % 1 1 !
46: CONST ORTHO_AC : AM NP% : !

AmNp-93Oga.tdb: ORTHO_AC, type code %, sha256 cfa44b10057e67b3…

51: PHASE ORTHO_AC % 1 1 !
52: CONST ORTHO_AC : NP : !

Example references (1 of 1; assessments first):

doi:10.1016/0925-8388(93)90636-2 Toru Ogawa, Alloying behaviour among U, Np, Pu and Am predicted with the Brewer valence bond model, Journal of Alloys and Compounds 194, 1-7 (1993).
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}
}