Pu–U phases

12 phases (tier A 5, liquid 1, needs_review 6); 11 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 · Pu–U system page · Markdown · field reference

Phases of the Pu–U system (12)
Phase	Structure	Basis	Stability (calculated)	TDB models
ORTHORHOMBIC_A20 phase:pu-u:a20-orthorhombic	alpha-U · A20 · oC4 · Cmcm (63)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–1047.02 K, x(U) 0.86227–1	4
TETRAGONAL_A6 phase:pu-u:a6-tetragonal	In · A6 · tI2 · I4/mmm (139)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 713.15–774.7 K, x(U) 0–0.01458	4
BCC_A2 phase:pu-u:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 712.8–3999.24 K, x(U) 0–1	4
FCC_A1 phase:pu-u:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 589.42–761.9 K, x(U) 0–0.01259	4
HCP_A3 phase:pu-u:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 4 calculated diagram(s)	4
LIQUID phase:pu-u:liquid	liquid	liquid	stable in 4 of 4 calculated diagram(s): 881.39–4000 K, x(U) 0–1	4
ALPHA_PU phase:pu-u:pu-alpha		needs_review	stable in 4 of 4 calculated diagram(s): 300–397.62 K, x(U) 0–0.00228	4
BETA_PU phase:pu-u:pu-beta		needs_review	stable in 4 of 4 calculated diagram(s): 396.75–553.62 K, x(U) 0–0.0212	4
GAMMA_PU phase:pu-u:pu-gamma		needs_review	stable in 4 of 4 calculated diagram(s): 470.42–614.42 K, x(U) 0–0.00478	4
PUU_ETA phase:pu-u:puu-eta		needs_review	stable in 4 of 4 calculated diagram(s): 450.47–980.56 K, x(U) 0.01304–0.77956	4
PUU_ZETA phase:pu-u:puu-zeta		needs_review	stable in 4 of 4 calculated diagram(s): 300–870.93 K, x(U) 0.14262–0.76791	4
TETRAGONAL_U phase:pu-u:u-tetragonal		needs_review	stable in 4 of 4 calculated diagram(s): 833.33–1049.05 K, x(U) 0.68067–1	4

ORTHORHOMBIC_A20 (Pu–U)

Id: phase:pu-u:a20-orthorhombic; status assigned
Structure: alpha-U · A20 · oC4 · Cmcm (63); type st:a20-alpha-u-oc4; tier A: standard phase name; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 300–1047.02 K, x(U) 0.86227–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:a20-orthorhombic
tdb: tdb:PuU-10Kur.tdb:ORTHORHOMBIC_A20, tdb:PuU-15Per.tdb:ORTHORHOMBIC_A20, tdb:PuU-23Fou.tdb:ORTHORHOMBIC_A20, tdb:PuU-99Kur.tdb:ORTHORHOMBIC_A20

TDB models of ORTHORHOMBIC_A20 (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: ORTHORHOMBIC_A20, type code %, sha256 ae973a5f25fff5bd…

60: PHASE ORTHORHOMBIC_A20 % 1 1 !
61: CONST ORTHORHOMBIC_A20 : PU U% : !

PuU-15Per.tdb: ORTHORHOMBIC_A20, type code %, sha256 b2766bcd4fb5f7f5…

63: PHASE ORTHORHOMBIC_A20 % 1 1 !
64: CONST ORTHORHOMBIC_A20 : PU U% : !

PuU-23Fou.tdb: ORTHORHOMBIC_A20, type code %, sha256 b15fc83561b28556…

66: PHASE ORTHORHOMBIC_A20 % 1 1 !
67: CONST ORTHORHOMBIC_A20 : PU U% : !

PuU-99Kur.tdb: ORTHORHOMBIC_A20, type code %, sha256 f7466d1c08e57111…

62: PHASE ORTHORHOMBIC_A20 % 1 1 !
63: CONST ORTHORHOMBIC_A20 : PU U% : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

TETRAGONAL_A6 (Pu–U)

Id: phase:pu-u:a6-tetragonal; status assigned
Structure: In · A6 · tI2 · I4/mmm (139); type st:a6-in-ti2; tier A: standard phase name; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 713.15–774.7 K, x(U) 0–0.01458
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:a6-tetragonal
tdb: tdb:PuU-10Kur.tdb:TETRAGONAL_A6, tdb:PuU-15Per.tdb:TETRAGONAL_A6, tdb:PuU-23Fou.tdb:TETRAGONAL_A6, tdb:PuU-99Kur.tdb:TETRAGONAL_A6

TDB models of TETRAGONAL_A6 (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: TETRAGONAL_A6, type code %, sha256 ae973a5f25fff5bd…

40: PHASE TETRAGONAL_A6 % 1 1 !
41: CONST TETRAGONAL_A6 : PU% U : !

PuU-15Per.tdb: TETRAGONAL_A6, type code %, sha256 b2766bcd4fb5f7f5…

43: PHASE TETRAGONAL_A6 % 1 1 !
44: CONST TETRAGONAL_A6 : PU% U : !

PuU-23Fou.tdb: TETRAGONAL_A6, type code %, sha256 b15fc83561b28556…

46: PHASE TETRAGONAL_A6 % 1 1 !
47: CONST TETRAGONAL_A6 : PU : !

PuU-99Kur.tdb: TETRAGONAL_A6, type code %, sha256 f7466d1c08e57111…

42: PHASE TETRAGONAL_A6 % 1 1 !
43: CONST TETRAGONAL_A6 : PU% U : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

BCC_A2 (Pu–U)

Id: phase:pu-u: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 4 of 4 calculated diagram(s): 712.8–3999.24 K, x(U) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:bcc-a2
tdb: tdb:PuU-10Kur.tdb:BCC_A2, tdb:PuU-15Per.tdb:BCC_A2, tdb:PuU-23Fou.tdb:BCC_A2, tdb:PuU-99Kur.tdb:BCC_A2

TDB models of BCC_A2 (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: BCC_A2, type code %B, sha256 ae973a5f25fff5bd…

30: PHASE BCC_A2 %B 2 1 3 !
31: CONST BCC_A2 : PU% U% : VA : !

PuU-15Per.tdb: BCC_A2, type code %B, sha256 b2766bcd4fb5f7f5…

33: PHASE BCC_A2 %B 2 1 3 !
34: CONST BCC_A2 : PU% U% : VA : !

PuU-23Fou.tdb: BCC_A2, type code %B, sha256 b15fc83561b28556…

36: PHASE BCC_A2 %B 2 1 3 !
37: CONST BCC_A2 : PU% U% : VA : !

PuU-99Kur.tdb: BCC_A2, type code %B, sha256 f7466d1c08e57111…

32: PHASE BCC_A2 %B 2 1 3 !
33: CONST BCC_A2 : PU% U% : VA : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

FCC_A1 (Pu–U)

Id: phase:pu-u: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 4 of 4 calculated diagram(s): 589.42–761.9 K, x(U) 0–0.01259
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:fcc-a1
tdb: tdb:PuU-10Kur.tdb:FCC_A1, tdb:PuU-15Per.tdb:FCC_A1, tdb:PuU-23Fou.tdb:FCC_A1, tdb:PuU-99Kur.tdb:FCC_A1

TDB models of FCC_A1 (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: FCC_A1, type code %A, sha256 ae973a5f25fff5bd…

25: PHASE FCC_A1 %A 2 1 1 !
26: CONST FCC_A1 : PU% U : VA : !

PuU-15Per.tdb: FCC_A1, type code %A, sha256 b2766bcd4fb5f7f5…

28: PHASE FCC_A1 %A 2 1 1 !
29: CONST FCC_A1 : PU% U : VA : !

PuU-23Fou.tdb: FCC_A1, type code %A, sha256 b15fc83561b28556…

31: PHASE FCC_A1 %A 2 1 1 !
32: CONST FCC_A1 : PU% U : VA : !

PuU-99Kur.tdb: FCC_A1, type code %A, sha256 f7466d1c08e57111…

27: PHASE FCC_A1 %A 2 1 1 !
28: CONST FCC_A1 : PU% U : VA : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

HCP_A3 (Pu–U)

Id: phase:pu-u: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 4 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:hcp-a3
tdb: tdb:PuU-10Kur.tdb:HCP_A3, tdb:PuU-15Per.tdb:HCP_A3, tdb:PuU-23Fou.tdb:HCP_A3, tdb:PuU-99Kur.tdb:HCP_A3

TDB models of HCP_A3 (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: HCP_A3, type code %A, sha256 ae973a5f25fff5bd…

35: PHASE HCP_A3 %A 2 1 0.5 !
36: CONST HCP_A3 : PU U : VA : !

PuU-15Per.tdb: HCP_A3, type code %A, sha256 b2766bcd4fb5f7f5…

38: PHASE HCP_A3 %A 2 1 0.5 !
39: CONST HCP_A3 : PU : VA : !

PuU-23Fou.tdb: HCP_A3, type code %A, sha256 b15fc83561b28556…

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

PuU-99Kur.tdb: HCP_A3, type code %A, sha256 f7466d1c08e57111…

37: PHASE HCP_A3 %A 2 1 0.5 !
38: CONST HCP_A3 : PU : VA : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

LIQUID (Pu–U)

Id: phase:pu-u:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 881.39–4000 K, x(U) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:liquid
tdb: tdb:PuU-10Kur.tdb:LIQUID, tdb:PuU-15Per.tdb:LIQUID, tdb:PuU-23Fou.tdb:LIQUID, tdb:PuU-99Kur.tdb:LIQUID

TDB models of LIQUID (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: LIQUID, type code %, sha256 ae973a5f25fff5bd…

20: PHASE LIQUID:L % 1 1 !
21: CONST LIQUID:L : PU U : !

PuU-15Per.tdb: LIQUID, type code %, sha256 b2766bcd4fb5f7f5…

23: PHASE LIQUID:L % 1 1 !
24: CONST LIQUID:L : PU U : !

PuU-23Fou.tdb: LIQUID, type code %, sha256 b15fc83561b28556…

26: PHASE LIQUID:L % 1 1 !
27: CONST LIQUID:L : PU U : !

PuU-99Kur.tdb: LIQUID, type code %, sha256 f7466d1c08e57111…

22: PHASE LIQUID:L % 1 1 !
23: CONST LIQUID:L : PU U : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

ALPHA_PU (Pu–U)

Id: phase:pu-u:pu-alpha; status needs_review
No structure assigned. Why: no_structure_token; off_stoichiometric_model
Candidate (sgte_mmc2): alpha-Pu · mP16 · P2_1/m (11) — Hallstedt 2025 mmc2 row for ALPHA_PU: Pu (alpha)
Candidate (tdb_comment): alpha-Pu · mP16 · P2_1/m — PuU-10Kur.tdb: 'Prototype alpha-Pu (mP16, P2_1/m)'
Candidate (tdb_comment): alpha-Pu · mP16 · P2_1/m — PuU-15Per.tdb: 'Prototype alpha-Pu (mP16, P2_1/m)'
Candidate (tdb_comment): alpha-Pu · mP16 · P2_1/m — PuU-23Fou.tdb: 'Prototype alpha-Pu (mP16, P2_1/m)'
Candidate (tdb_comment): alpha-Pu · mP16 · P2_1/m — PuU-99Kur.tdb: 'Prototype alpha-Pu (mP16, P2_1/m)'
Stability: stable in 4 of 4 calculated diagram(s): 300–397.62 K, x(U) 0–0.00228
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:pu-alpha
tdb: tdb:PuU-10Kur.tdb:ALPHA_PU, tdb:PuU-15Per.tdb:ALPHA_PU, tdb:PuU-23Fou.tdb:ALPHA_PU, tdb:PuU-99Kur.tdb:ALPHA_PU

TDB models of ALPHA_PU (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: ALPHA_PU, type code %, sha256 ae973a5f25fff5bd…

45: PHASE ALPHA_PU % 1 1 !
46: CONST ALPHA_PU : PU% U : !

PuU-15Per.tdb: ALPHA_PU, type code %, sha256 b2766bcd4fb5f7f5…

48: PHASE ALPHA_PU % 1 1 !
49: CONST ALPHA_PU : PU : !

PuU-23Fou.tdb: ALPHA_PU, type code %, sha256 b15fc83561b28556…

51: PHASE ALPHA_PU % 1 1 !
52: CONST ALPHA_PU : PU : !

PuU-99Kur.tdb: ALPHA_PU, type code %, sha256 f7466d1c08e57111…

47: PHASE ALPHA_PU % 1 1 !
48: CONST ALPHA_PU : PU : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

BETA_PU (Pu–U)

Id: phase:pu-u:pu-beta; status needs_review
No structure assigned. Why: no_structure_token; off_stoichiometric_model
Candidate (sgte_mmc2): beta-Pu · mC34 · C2/m (12) — Hallstedt 2025 mmc2 row for BETA_PU: Pu (beta)
Candidate (tdb_comment): beta-Pu · mC34 · C2/m — PuU-10Kur.tdb: 'Prototype beta-Pu (mC34, C2/m)'
Candidate (tdb_comment): beta-Pu · mC34 · C2/m — PuU-15Per.tdb: 'Prototype beta-Pu (mC34, C2/m)'
Candidate (tdb_comment): beta-Pu · mC34 · C2/m — PuU-23Fou.tdb: 'Prototype beta-Pu (mC34, C2/m)'
Candidate (tdb_comment): beta-Pu · mC34 · C2/m — PuU-99Kur.tdb: 'Prototype beta-Pu (mC34, C2/m)'
Stability: stable in 4 of 4 calculated diagram(s): 396.75–553.62 K, x(U) 0–0.0212
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:pu-beta
tdb: tdb:PuU-10Kur.tdb:BETA_PU, tdb:PuU-15Per.tdb:BETA_PU, tdb:PuU-23Fou.tdb:BETA_PU, tdb:PuU-99Kur.tdb:BETA_PU

TDB models of BETA_PU (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: BETA_PU, type code %, sha256 ae973a5f25fff5bd…

50: PHASE BETA_PU % 1 1 !
51: CONST BETA_PU : PU% U : !

PuU-15Per.tdb: BETA_PU, type code %, sha256 b2766bcd4fb5f7f5…

53: PHASE BETA_PU % 1 1 !
54: CONST BETA_PU : PU% U : !

PuU-23Fou.tdb: BETA_PU, type code %, sha256 b15fc83561b28556…

56: PHASE BETA_PU % 1 1 !
57: CONST BETA_PU : PU% U : !

PuU-99Kur.tdb: BETA_PU, type code %, sha256 f7466d1c08e57111…

52: PHASE BETA_PU % 1 1 !
53: CONST BETA_PU : PU% U : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

GAMMA_PU (Pu–U)

Id: phase:pu-u:pu-gamma; status needs_review
No structure assigned. Why: no_structure_token; off_stoichiometric_model
Candidate (sgte_mmc2): gamma-Pu · oF8 · Fddd (70) — Hallstedt 2025 mmc2 row for GAMMA_PU: Hg4In, Pu (gamma)
Candidate (tdb_comment): gamma-Pu · oF8 · Fddd — PuU-10Kur.tdb: 'Prototype gamma-Pu (oF8, Fddd)'
Candidate (tdb_comment): gamma-Pu · oF8 · Fddd — PuU-15Per.tdb: 'Prototype gamma-Pu (oF8, Fddd)'
Candidate (tdb_comment): gamma-Pu · oF8 · Fddd — PuU-23Fou.tdb: 'Prototype gamma-Pu (oF8, Fddd)'
Candidate (tdb_comment): gamma-Pu · oF8 · Fddd — PuU-99Kur.tdb: 'Prototype gamma-Pu (oF8, Fddd)'
Stability: stable in 4 of 4 calculated diagram(s): 470.42–614.42 K, x(U) 0–0.00478
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:pu-gamma
tdb: tdb:PuU-10Kur.tdb:GAMMA_PU, tdb:PuU-15Per.tdb:GAMMA_PU, tdb:PuU-23Fou.tdb:GAMMA_PU, tdb:PuU-99Kur.tdb:GAMMA_PU

TDB models of GAMMA_PU (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: GAMMA_PU, type code %, sha256 ae973a5f25fff5bd…

55: PHASE GAMMA_PU % 1 1 !
56: CONST GAMMA_PU : PU% U : !

PuU-15Per.tdb: GAMMA_PU, type code %, sha256 b2766bcd4fb5f7f5…

58: PHASE GAMMA_PU % 1 1 !
59: CONST GAMMA_PU : PU% U : !

PuU-23Fou.tdb: GAMMA_PU, type code %, sha256 b15fc83561b28556…

61: PHASE GAMMA_PU % 1 1 !
62: CONST GAMMA_PU : PU : !

PuU-99Kur.tdb: GAMMA_PU, type code %, sha256 f7466d1c08e57111…

57: PHASE GAMMA_PU % 1 1 !
58: CONST GAMMA_PU : PU% U : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

PUU_ETA (Pu–U)

Id: phase:pu-u:puu-eta; status needs_review
No structure assigned. Why: no_structure_token; off_stoichiometric_model
Candidate (sgte_mmc2): (PuU-eta) · tP52 — Hallstedt 2025 mmc2 row for PUU_ETA: PuU-eta
Stability: stable in 4 of 4 calculated diagram(s): 450.47–980.56 K, x(U) 0.01304–0.77956
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:puu-eta
tdb: tdb:PuU-10Kur.tdb:PUU_ETA, tdb:PuU-15Per.tdb:PUU_ETA, tdb:PuU-23Fou.tdb:PUU_ETA, tdb:PuU-99Kur.tdb:PUU_ETA

TDB models of PUU_ETA (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: PUU_ETA, type code %, sha256 ae973a5f25fff5bd…

75: PHASE PUU_ETA % 1 1 !
76: CONST PUU_ETA : PU U : !

PuU-15Per.tdb: PUU_ETA, type code %, sha256 b2766bcd4fb5f7f5…

78: PHASE PUU_ETA % 1 1 !
79: CONST PUU_ETA : PU U : !

PuU-23Fou.tdb: PUU_ETA, type code %, sha256 b15fc83561b28556…

81: PHASE PUU_ETA % 1 1 !
82: CONST PUU_ETA : PU U : !

PuU-99Kur.tdb: PUU_ETA, type code %, sha256 f7466d1c08e57111…

77: PHASE PUU_ETA % 1 1 !
78: CONST PUU_ETA : PU U : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

PUU_ZETA (Pu–U)

Id: phase:pu-u:puu-zeta; status needs_review
No structure assigned. Why: no_structure_token; off_stoichiometric_model
Candidate (sgte_mmc2): PuU-zeta · hR58 · R-3m (166) — Hallstedt 2025 mmc2 row for PUU_ZETA: NpU-zeta, PuU-zeta
Candidate (tdb_comment): PuU-zeta · hR58 · R-3m — PuU-10Kur.tdb: 'Prototype PuU-zeta (hR58, R-3m)'
Candidate (tdb_comment): PuU-zeta · hR58 · R-3m — PuU-15Per.tdb: 'Prototype PuU-zeta (hR58, R-3m)'
Candidate (tdb_comment): PuU-zeta · hR58 · R-3m — PuU-23Fou.tdb: 'Prototype PuU-zeta (hR58, R-3m)'
Candidate (tdb_comment): PuU-zeta · hR58 · R-3m — PuU-99Kur.tdb: 'Prototype PuU-zeta (hR58, R-3m)'
Stability: stable in 4 of 4 calculated diagram(s): 300–870.93 K, x(U) 0.14262–0.76791
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:puu-zeta
tdb: tdb:PuU-10Kur.tdb:PUU_ZETA, tdb:PuU-15Per.tdb:PUU_ZETA, tdb:PuU-23Fou.tdb:PUU_ZETA, tdb:PuU-99Kur.tdb:PUU_ZETA

TDB models of PUU_ZETA (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: PUU_ZETA, type code %, sha256 ae973a5f25fff5bd…

70: PHASE PUU_ZETA % 1 1 !
71: CONST PUU_ZETA : PU U : !

PuU-15Per.tdb: PUU_ZETA, type code %, sha256 b2766bcd4fb5f7f5…

73: PHASE PUU_ZETA % 1 1 !
74: CONST PUU_ZETA : PU U : !

PuU-23Fou.tdb: PUU_ZETA, type code %, sha256 b15fc83561b28556…

76: PHASE PUU_ZETA % 1 1 !
77: CONST PUU_ZETA : PU U : !

PuU-99Kur.tdb: PUU_ZETA, type code %, sha256 f7466d1c08e57111…

72: PHASE PUU_ZETA % 1 1 !
73: CONST PUU_ZETA : PU U : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
assessment that models this phase

TETRAGONAL_U (Pu–U)

Id: phase:pu-u:u-tetragonal; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:TETRAGONAL; no_structure_token
Candidate (sgte_mmc2): beta-U · A_b · tP30 · P4_2/mnm (136) — Hallstedt 2025 mmc2 row for TETRAGONAL_U: beta-U
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — PuU-10Kur.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — PuU-15Per.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — PuU-23Fou.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Candidate (tdb_comment): beta-U · tP30 · P4_2/mnm, SB: A_b — PuU-99Kur.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
Stability: stable in 4 of 4 calculated diagram(s): 833.33–1049.05 K, x(U) 0.68067–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:pu-u:u-tetragonal
tdb: tdb:PuU-10Kur.tdb:TETRAGONAL_U, tdb:PuU-15Per.tdb:TETRAGONAL_U, tdb:PuU-23Fou.tdb:TETRAGONAL_U, tdb:PuU-99Kur.tdb:TETRAGONAL_U

TDB models of TETRAGONAL_U (4): PHASE and CONSTITUENT statements as written

PuU-10Kur.tdb: TETRAGONAL_U, type code %, sha256 ae973a5f25fff5bd…

65: PHASE TETRAGONAL_U % 1 1 !
66: CONST TETRAGONAL_U : PU U% : !

PuU-15Per.tdb: TETRAGONAL_U, type code %, sha256 b2766bcd4fb5f7f5…

68: PHASE TETRAGONAL_U % 1 1 !
69: CONST TETRAGONAL_U : PU U% : !

PuU-23Fou.tdb: TETRAGONAL_U, type code %, sha256 b15fc83561b28556…

71: PHASE TETRAGONAL_U % 1 1 !
72: CONST TETRAGONAL_U : PU U% : !

PuU-99Kur.tdb: TETRAGONAL_U, type code %, sha256 f7466d1c08e57111…

67: PHASE TETRAGONAL_U % 1 1 !
68: CONST TETRAGONAL_U : PU U% : !

Example references (3 of 3; assessments first):

doi:10.1016/j.calphad.2022.102523 P. Fouquet-Métivier, P.M. Martin, D. Manara, K. Dardenne, J. Rothe, P.C.M. Fossati et al., Investigation of the solid/liquid phase transitions in the U–Pu–O system, Calphad 80, 102523 (2023).
assessment that models this phase
doi:10.1016/j.jnucmat.2014.12.101 A. Perron, P.E.A. Turchi, A. Landa, P. Söderlind, B. Ravat, B. Oudot et al., The Pu–U–Am system: An ab initio informed CALPHAD thermodynamic study, Journal of Nuclear Materials 458, 425-441 (2015).
assessment that models this phase
doi:10.1016/S0364-5916(00)00004-3 M. Kurata, Calphad, 23, 305-37(1999).
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}
}