# Ni–U phases

> Ni–U system: 13 phases (tier A 7, tier C 2, liquid 1, needs_review 3); 12 stable in a calculated diagram in the ORCHID phase registry, with names, structure type when the stored evidence supports an assignment under the stated tier rules, calculated stability, verbatim TDB PHASE/CONSTITUENT statements and example references.

HTML: https://data.orchid-project.org/phases/pages/NI-U.html · Markdown: https://data.orchid-project.org/phases/pages/NI-U.md

13 phases (tier A 7, tier C 2, liquid 1, needs_review 3); 12 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](https://orchid-project.org/phases/?q=NI-U) · [full JSON](https://data.orchid-project.org/phases/systems/NI-U.json) · [Ni–U system page](https://data.orchid-project.org/systems/NI-U.html) · [Markdown](https://data.orchid-project.org/phases/pages/NI-U.md) · [field reference](https://data.orchid-project.org/phases/SCHEMA.md)

Table: Phases of the Ni–U system (13)

| Phase | Structure | Basis | Stability (calculated) | Literature values | TDB models |
|---|---|---|---|---:|---:|
| [ORTHORHOMBIC_A20](#phase-ni-u-a20-orthorhombic); _phase:ni-u:a20-orthorhombic_ | alpha-U · A20 · oC4 · Cmcm (63) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1047.02 K, x(U) 0.99994–1 | 0 | 1 |
| [BCC_A2](#phase-ni-u-bcc-a2); _phase:ni-u:bcc-a2_ | W · A2 · cI2 · Im-3m (229) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 1032.92–1407.99 K, x(U) 0.97548–1 | 4 | 1 |
| [FCC_A1](#phase-ni-u-fcc-a1); _phase:ni-u:fcc-a1_ | Cu · A1 · cF4 · Fm-3m (225) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1749.24 K, x(U) 0–0.01259 | 2 | 1 |
| [HCP_A3](#phase-ni-u-hcp-a3); _phase:ni-u:hcp-a3_ | Mg · A3 · hP2 · P6_3/mmc (194) | tier A: standard phase name | not stable in 1 calculated diagram(s) | 0 | 1 |
| [LIQUID](#phase-ni-u-liquid); _phase:ni-u:liquid_ | liquid | liquid | stable in 1 of 1 calculated diagram(s): 1015.07–4000 K, x(U) 0–1 | 18 | 1 |
| [NI2U_C14](#phase-ni-u-ni2u-c14); _phase:ni-u:ni2u-c14_ | MgZn2 · C14 · hP12 · P6_3/mmc (194) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1259.2 K, x(U) 0.33333–0.33333 | 4 | 1 |
| [NI3U](#phase-ni-u-ni3u); _phase:ni-u:ni3u_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–1536.06 K, x(U) 0.23–0.23 | 2 | 1 |
| [NI5U_C15B](#phase-ni-u-ni5u-c15b); _phase:ni-u:ni5u-c15b_ | AuBe5 · C15_b · cF24 · F-43m (216) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1583.48 K, x(U) 0.16667–0.16667 | 5 | 1 |
| [NI7U2_D2D](#phase-ni-u-ni7u2-d2d); _phase:ni-u:ni7u2-d2d_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 300–1570.32 K, x(U) 0.22–0.22 | 0 | 1 |
| [NI7U5](#phase-ni-u-ni7u5); _phase:ni-u:ni7u5_ | Ni7U5 · hR54 · R-3 (148) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 300–1093.01 K, x(U) 0.41667–0.41667 | 4 | 1 |
| [NI9U7](#phase-ni-u-ni9u7); _phase:ni-u:ni9u7_ | Ni9U7 · mC46 · C2/m (12) | tier C: assessor-stated (Hallstedt 2025 crystallographic table) | stable in 1 of 1 calculated diagram(s): 300–1055.94 K, x(U) 0.4375–0.4375 | 4 | 1 |
| [NIU6_D2C](#phase-ni-u-niu6-d2c); _phase:ni-u:niu6-d2c_ | MnU6 · D2_c · tI28 · I4/mcm (140) | tier A: standard phase name | stable in 1 of 1 calculated diagram(s): 300–1063.55 K, x(U) 0.85714–0.85714 | 6 | 1 |
| [TETRAGONAL_U](#phase-ni-u-u-tetragonal); _phase:ni-u:u-tetragonal_ |  | needs_review | stable in 1 of 1 calculated diagram(s): 935–1047.02 K, x(U) 0.98983–1 | 2 | 1 |

## ORTHORHOMBIC_A20 (Ni–U)

- Id: `phase:ni-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 1 of 1 calculated diagram(s): 300–1047.02 K, x(U) 0.99994–1
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:a20-orthorhombic)

Names (2): _corpus: _corpus:phase:ni-u:a20-orthorhombic  
_tdb: _tdb:NiU-09Wan.tdb:ORTHORHOMBIC_A20  


### TDB models of ORTHORHOMBIC_A20 (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): ORTHORHOMBIC_A20, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
43: PHASE ORTHORHOMBIC_A20 % 1 1 !
44: CONST ORTHORHOMBIC_A20 : NI U% : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase_

## BCC_A2 (Ni–U)

- Id: `phase:ni-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 1 of 1 calculated diagram(s): 1032.92–1407.99 K, x(U) 0.97548–1
- Literature: 4 values (4 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:bcc-a2)

Names (3): _corpus: _corpus:phase:ni-u:bcc-a2  
_paper: _paper:10.1016/j.jallcom.2009.07.168:γU  
_tdb: _tdb:NiU-09Wan.tdb:BCC_A2  


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

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): BCC_A2, type code %B, sha256 `9f6aef6a1ab79ad3…`

~~~~text
33: PHASE BCC_A2 %B 2 1 3 !
34: CONST BCC_A2 : NI U% : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## FCC_A1 (Ni–U)

- Id: `phase:ni-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 1 of 1 calculated diagram(s): 300–1749.24 K, x(U) 0–0.01259
- Literature: 2 values (2 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:fcc-a1)

Names (3): _corpus: _corpus:phase:ni-u:fcc-a1  
_paper: _paper:10.1016/j.jallcom.2009.07.168:(Ni)  
_tdb: _tdb:NiU-09Wan.tdb:FCC_A1  


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

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): FCC_A1, type code %A, sha256 `9f6aef6a1ab79ad3…`

~~~~text
28: PHASE FCC_A1 %A 2 1 1 !
29: CONST FCC_A1 : NI% U : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## HCP_A3 (Ni–U)

- Id: `phase:ni-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 1 calculated diagram(s)
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:hcp-a3)

Names (2): _corpus: _corpus:phase:ni-u:hcp-a3  
_tdb: _tdb:NiU-09Wan.tdb:HCP_A3  


### TDB models of HCP_A3 (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): HCP_A3, type code %A, sha256 `9f6aef6a1ab79ad3…`

~~~~text
38: PHASE HCP_A3 %A 2 1 0.5 !
39: CONST HCP_A3 : NI U : VA : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase_

## LIQUID (Ni–U)

- Id: `phase:ni-u:liquid`; status `assigned`
- Structure: liquid; type `st:liquid`; liquid; confidence high
- Stability: stable in 1 of 1 calculated diagram(s): 1015.07–4000 K, x(U) 0–1
- Literature: 18 values (18 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:liquid)

Names (3): _corpus: _corpus:phase:ni-u:liquid  
_paper: _paper:10.1016/j.jallcom.2009.07.168:L  
_tdb: _tdb:NiU-09Wan.tdb:LIQUID  


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

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): LIQUID, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
23: PHASE LIQUID:L % 1 1 !
24: CONST LIQUID:L : NI U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## NI2U_C14 (Ni–U)

- Id: `phase:ni-u:ni2u-c14`; status `assigned`
- Structure: MgZn2 · C14 · hP12 · P6_3/mmc (194); type `st:c14-mgzn2-hp12`; tier A: standard phase name; confidence high
- Stoichiometry: Ni 0.6667, U 0.3333
- Stability: stable in 1 of 1 calculated diagram(s): 300–1259.2 K, x(U) 0.33333–0.33333
- Literature: 4 values (4 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:ni2u-c14)

Names (3): _corpus: _corpus:phase:ni-u:ni2u-c14  
_paper: _paper:10.1016/j.jallcom.2009.07.168:UNi2  
_tdb: _tdb:NiU-09Wan.tdb:NI2U_C14  


### TDB models of NI2U_C14 (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): NI2U_C14, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
68: PHASE NI2U_C14 % 2 2 1 !
69: CONST NI2U_C14 : NI : U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## NI3U (Ni–U)

- Id: `phase:ni-u:ni3u`; status `needs_review`
- No structure assigned. Why: no_on_hull_entry_in_both; no_structure_token; sgte_mmc2_row_incomplete
- Candidate (literature_printed): (Ni3U) · ? — printed with a label mapped to this phase
- Candidate (sgte_mmc2): (Ni3U) — Hallstedt 2025 mmc2 row for NI3U: Ni3U
- Stoichiometry: Ni 0.7700, U 0.2300
- Stability: stable in 1 of 1 calculated diagram(s): 300–1536.06 K, x(U) 0.23–0.23
- Literature: 2 values (2 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:ni3u)

Names (3): _corpus: _corpus:phase:ni-u:ni3u  
_paper: _paper:10.1016/j.jallcom.2009.07.168:δ  
_tdb: _tdb:NiU-09Wan.tdb:NI3U  


### TDB models of NI3U (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): NI3U, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
63: PHASE NI3U % 2 0.77 0.23 !
64: CONST NI3U : NI : U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## NI5U_C15B (Ni–U)

- Id: `phase:ni-u:ni5u-c15b`; status `assigned`
- Structure: AuBe5 · C15_b · cF24 · F-43m (216); type `st:c15-b-aube5-cf24`; tier A: standard phase name; confidence high
- Caveat: DFT agrees: on-hull mp-aaaaaefe and oqmd-17847, space group 216
- Stoichiometry: Ni 0.8333, U 0.1667
- Stability: stable in 1 of 1 calculated diagram(s): 300–1583.48 K, x(U) 0.16667–0.16667
- Literature: 5 values (5 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:ni5u-c15b)

Names (5): _corpus: _corpus:phase:ni-u:ni5u-c15b  
_mp: _mp:mp-aaaaaefe  
_oqmd: _oqmd:oqmd-17847  
_paper: _paper:10.1016/j.jallcom.2009.07.168:UNi5  
_tdb: _tdb:NiU-09Wan.tdb:NI5U_C15B  


### TDB models of NI5U_C15B (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): NI5U_C15B, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
53: PHASE NI5U_C15B % 2 5 1 !
54: CONST NI5U_C15B : NI : U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## NI7U2_D2D (Ni–U)

- Id: `phase:ni-u:ni7u2-d2d`; status `needs_review`
- No structure assigned. Why: assessment_declared_blocked_by:stoichiometry_contradicts_D2_d; stoichiometry_contradicts_D2_d:NiU-09Wan.tdb
- Candidate (name_token): CaCu5 · D2_d · hP6 · P6/mmm (191) — Strukturbericht/word 'D2D' in the TDB name
- Candidate (sgte_mmc2): CaCu5 · D2_d · hP6 · P6/mmm (191) — Hallstedt 2025 mmc2 row for NI7U2_D2D: Ni7U2
- Candidate (tdb_comment): CaCu5 · hP6 · P6/mmm — NiU-09Wan.tdb: 'Prototype CaCu5 (hP6, P6/mmm), epsilon'
- Stoichiometry: Ni 0.7800, U 0.2200
- Stability: stable in 1 of 1 calculated diagram(s): 300–1570.32 K, x(U) 0.22–0.22
- Literature: 0 values (0 accepted) from 0 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:ni7u2-d2d)

Names (2): _corpus: _corpus:phase:ni-u:ni7u2-d2d  
_tdb: _tdb:NiU-09Wan.tdb:NI7U2_D2D  


### TDB models of NI7U2_D2D (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): NI7U2_D2D, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
58: PHASE NI7U2_D2D % 2 0.78 0.22 !
59: CONST NI7U2_D2D : NI : U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase_

## NI7U5 (Ni–U)

- Id: `phase:ni-u:ni7u5`; status `assigned`
- Structure: Ni7U5 · hR54 · R-3 (148); type `st:ni7u5-hr54`; 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](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stoichiometry: Ni 0.5833, U 0.4167
- Stability: stable in 1 of 1 calculated diagram(s): 300–1093.01 K, x(U) 0.41667–0.41667
- Literature: 4 values (4 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:ni7u5)

Names (3): _corpus: _corpus:phase:ni-u:ni7u5  
_paper: _paper:10.1016/j.jallcom.2009.07.168:U5Ni7  
_tdb: _tdb:NiU-09Wan.tdb:NI7U5  


### TDB models of NI7U5 (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): NI7U5, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
73: PHASE NI7U5 % 2 7 5 !
74: CONST NI7U5 : NI : U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## NI9U7 (Ni–U)

- Id: `phase:ni-u:ni9u7`; status `assigned`
- Structure: Ni9U7 · mC46 · C2/m (12); type `st:ni9u7-mc46`; 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](https://doi.org/10.1016/j.calphad.2025.102833)
- Caveat: not certain from the name or DFT alone (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
- Stoichiometry: Ni 0.5625, U 0.4375
- Stability: stable in 1 of 1 calculated diagram(s): 300–1055.94 K, x(U) 0.4375–0.4375
- Literature: 4 values (4 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:ni9u7)

Names (3): _corpus: _corpus:phase:ni-u:ni9u7  
_paper: _paper:10.1016/j.jallcom.2009.07.168:U7Ni9  
_tdb: _tdb:NiU-09Wan.tdb:NI9U7  


### TDB models of NI9U7 (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): NI9U7, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
78: PHASE NI9U7 % 2 9 7 !
79: CONST NI9U7 : NI : U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## NIU6_D2C (Ni–U)

- Id: `phase:ni-u:niu6-d2c`; status `assigned`
- Structure: MnU6 · D2_c · tI28 · I4/mcm (140); type `st:d2-c-mnu6-ti28`; tier A: standard phase name; confidence high
- Stoichiometry: Ni 0.1429, U 0.8571
- Stability: stable in 1 of 1 calculated diagram(s): 300–1063.55 K, x(U) 0.85714–0.85714
- Literature: 6 values (6 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:niu6-d2c)

Names (3): _corpus: _corpus:phase:ni-u:niu6-d2c  
_paper: _paper:10.1016/j.jallcom.2009.07.168:U6Ni  
_tdb: _tdb:NiU-09Wan.tdb:NIU6_D2C  


### TDB models of NIU6_D2C (1): PHASE and CONSTITUENT statements as written

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): NIU6_D2C, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
83: PHASE NIU6_D2C % 2 1 6 !
84: CONST NIU6_D2C : NI : U : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for this phase_

## TETRAGONAL_U (Ni–U)

- Id: `phase:ni-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 — NiU-09Wan.tdb: 'Prototype beta-U (tP30, P4_2/mnm, SB: A_b)'
- Stability: stable in 1 of 1 calculated diagram(s): 935–1047.02 K, x(U) 0.98983–1
- Literature: 2 values (2 accepted) from 1 papers
- Interactive: [phase registry entry](https://orchid-project.org/phases/#phase:ni-u:u-tetragonal)

Names (4): _corpus: _corpus:phase:ni-u:u-tetragonal, corpus:phase:ni-u:tetragonal-u  
_paper: _paper:10.1016/j.jallcom.2009.07.168:βU  
_tdb: _tdb:NiU-09Wan.tdb:TETRAGONAL_U  


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

[NiU-09Wan.tdb](https://orchid-project.org/data/databases/sgte-binary/NiU-09Wan.tdb): TETRAGONAL_U, type code %, sha256 `9f6aef6a1ab79ad3…`

~~~~text
48: PHASE TETRAGONAL_U % 1 1 !
49: CONST TETRAGONAL_U : NI U% : !
~~~~

Example references (1 of 1; assessments first): 

- [doi:10.1016/j.jallcom.2009.07.168](https://doi.org/10.1016/j.jallcom.2009.07.168) C.P. Wang, Y. He, H.L. Zhang, X.J. Liu, Thermodynamic assessments of the U–Ni and Th–Ni systems, Journal of Alloys and Compounds 487, 126-131 (2009).  
_assessment that models this phase; reports values for 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). https://doi.org/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). https://doi.org/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.

```bibtex
@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}
}
```

---

Derived data CC BY 4.0 ([licence](https://creativecommons.org/licenses/by/4.0/)): cite the ORCHID phase registry and the sources named on the page (TDB assessments, Hallstedt 2025, Materials Project, OQMD). TDB statements are quoted as written; parameter expressions are not reproduced. Field reference: [SCHEMA.md](https://data.orchid-project.org/phases/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt).