Nb–P phases

10 phases (tier A 3, tier B 3, tier C 1, liquid 1, needs_review 2); 7 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 · Nb–P system page · Markdown · field reference

Phases of the Nb–P system (10)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:nb-p:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–2759.82 K, x(P) 0–0.06253	0	1
FCC_A1 phase:nb-p:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
HCP_A3 phase:nb-p: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:nb-p:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 519–4000 K, x(P) 0–1	0	1
NB3P phase:nb-p:nb3p	Ti3P · tP32 · P4_2/n (86)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–573.75 K, x(P) 0.25–0.25	4	1
NB7P4 phase:nb-p:nb7p4	Nb7P4 · mC44 · C2/m (12)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–1733.63 K, x(P) 0.36364–0.36364	8	1
NBP phase:nb-p:nbp	NbAs · tI8 · I4_1md (109)	tier B: DFT-supported (unique MP + OQMD match)	stable in 1 of 1 calculated diagram(s): 300–2003.03 K, x(P) 0.5–0.5	4	1
NBP2 phase:nb-p:nbp2	Ge2Os · mC12 · C2/m (12)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1302.59 K, x(P) 0.66667–0.66667	6	1
RED_P phase:nb-p:p-red		needs_review	stable in 1 of 1 calculated diagram(s): 300–914 K, x(P) 1–1	0	1
WHITE_P phase:nb-p:p-white		needs_review	not stable in 1 calculated diagram(s)	0	1

BCC_A2 (Nb–P)

Id: phase:nb-p: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): 300–2759.82 K, x(P) 0–0.06253
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:nb-p:bcc-a2
tdb: tdb:NbP-09Tok.tdb:BCC_A2

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

NbP-09Tok.tdb: BCC_A2, type code %B, sha256 ce209315ccfc4ebb…

32: PHASE BCC_A2 %B 2 1 3 !
33: CONST BCC_A2 : NB% P : VA : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase

FCC_A1 (Nb–P)

Id: phase:nb-p:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; 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

Names (2): corpus: corpus:phase:nb-p:fcc-a1
tdb: tdb:NbP-09Tok.tdb:FCC_A1

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

NbP-09Tok.tdb: FCC_A1, type code %A, sha256 ce209315ccfc4ebb…

27: PHASE FCC_A1 %A 2 1 1 !
28: CONST FCC_A1 : NB P : VA : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase

HCP_A3 (Nb–P)

Id: phase:nb-p: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

Names (2): corpus: corpus:phase:nb-p:hcp-a3
tdb: tdb:NbP-09Tok.tdb:HCP_A3

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

NbP-09Tok.tdb: HCP_A3, type code %A, sha256 ce209315ccfc4ebb…

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

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase

LIQUID (Nb–P)

Id: phase:nb-p:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 519–4000 K, x(P) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:nb-p:liquid
tdb: tdb:NbP-09Tok.tdb:LIQUID

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

NbP-09Tok.tdb: LIQUID, type code %, sha256 ce209315ccfc4ebb…

22: PHASE LIQUID:L % 1 1 !
23: CONST LIQUID:L : NB P : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase

NB3P (Nb–P)

Id: phase:nb-p:nb3p; status assigned
Structure: Ti3P · tP32 · P4_2/n (86); type st:ti3p-tp32; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: Nb 0.7500, P 0.2500
Stability: stable in 1 of 1 calculated diagram(s): 300–573.75 K, x(P) 0.25–0.25
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:nb-p:nb3p
mp: mp:mp-aaabctvk
oqmd: oqmd:oqmd-8004
paper: paper:10.2355/isijinternational.49.947:Nb3P
tdb: tdb:NbP-09Tok.tdb:NB3P

TDB models of NB3P (1): PHASE and CONSTITUENT statements as written

NbP-09Tok.tdb: NB3P, type code %, sha256 ce209315ccfc4ebb…

52: PHASE NB3P % 2 3 1 !
53: CONST NB3P : NB : P : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase; reports values for this phase

NB7P4 (Nb–P)

Id: phase:nb-p:nb7p4; status assigned
Structure: Nb7P4 · mC44 · C2/m (12); type st:nb7p4-mc44; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: Nb 0.6364, P 0.3636
Stability: stable in 1 of 1 calculated diagram(s): 300–1733.63 K, x(P) 0.36364–0.36364
Literature: 8 values (8 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:nb-p:nb7p4
mp: mp:mp-aaaabbac
oqmd: oqmd:oqmd-7444
paper: paper:10.2355/isijinternational.49.947:Nb7P4
tdb: tdb:NbP-09Tok.tdb:NB7P4

TDB models of NB7P4 (1): PHASE and CONSTITUENT statements as written

NbP-09Tok.tdb: NB7P4, type code %, sha256 ce209315ccfc4ebb…

57: PHASE NB7P4 % 2 7 4 !
58: CONST NB7P4 : NB : P : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase; reports values for this phase

NBP (Nb–P)

Id: phase:nb-p:nbp; status assigned
Structure: NbAs · tI8 · I4_1md (109); type st:nbas-ti8; tier B: DFT-supported (unique MP + OQMD match); confidence high
Stoichiometry: Nb 0.5000, P 0.5000
Stability: stable in 1 of 1 calculated diagram(s): 300–2003.03 K, x(P) 0.5–0.5
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:nb-p:nbp
mp: mp:mp-aaaaanvf
oqmd: oqmd:oqmd-14682
paper: paper:10.2355/isijinternational.49.947:NbP
tdb: tdb:NbP-09Tok.tdb:NBP

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

NbP-09Tok.tdb: NBP, type code %, sha256 ce209315ccfc4ebb…

62: PHASE NBP % 2 1 1 !
63: CONST NBP : NB : P : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase; reports values for this phase

NBP2 (Nb–P)

Id: phase:nb-p:nbp2; status assigned
Structure: Ge2Os · mC12 · C2/m (12); type st:ge2os-mc12; 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 (dft_space_group_12_matches_7_structure_types, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: Nb 0.3333, P 0.6667
Stability: stable in 1 of 1 calculated diagram(s): 300–1302.59 K, x(P) 0.66667–0.66667
Literature: 6 values (6 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:nb-p:nbp2
paper: paper:10.2355/isijinternational.49.947:NbP2
tdb: tdb:NbP-09Tok.tdb:NBP2

TDB models of NBP2 (1): PHASE and CONSTITUENT statements as written

NbP-09Tok.tdb: NBP2, type code %, sha256 ce209315ccfc4ebb…

67: PHASE NBP2 % 2 1 2 !
68: CONST NBP2 : NB : P : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase; reports values for this phase

RED_P (Nb–P)

Id: phase:nb-p:p-red; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:RED; no_structure_token
Candidate (sgte_mmc2): (Red P) — Hallstedt 2025 mmc2 row for RED_P: Red P
Stoichiometry: P 1.0000
Stability: stable in 1 of 1 calculated diagram(s): 300–914 K, x(P) 1–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:nb-p:p-red
tdb: tdb:NbP-09Tok.tdb:RED_P

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

NbP-09Tok.tdb: RED_P, type code %, sha256 ce209315ccfc4ebb…

47: PHASE RED_P % 1 1 !
48: CONST RED_P : P : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (2009).
assessment that models this phase

WHITE_P (Nb–P)

Id: phase:nb-p:p-white; status needs_review
No structure assigned. Why: name_has_descriptive_tokens:WHITE; no_structure_token
Candidate (sgte_mmc2): (White P) — Hallstedt 2025 mmc2 row for WHITE_P: White P
Stoichiometry: P 1.0000
Stability: not stable in 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:nb-p:p-white
tdb: tdb:NbP-09Tok.tdb:WHITE_P

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

NbP-09Tok.tdb: WHITE_P, type code %, sha256 ce209315ccfc4ebb…

42: PHASE WHITE_P % 1 1 !
43: CONST WHITE_P : P : !

Example references (1 of 1; assessments first):

doi:10.2355/isijinternational.49.947 Tatsuya Tokunaga, Naoko Hanaya, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of Phase Equilibria in the Fe–Nb–P Ternary System, ISIJ Int. 49, 947-956 (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}
}