K–Na phases

5 phases (tier A 4, liquid 1); 2 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 · K–Na system page · Markdown · field reference

Phases of the K–Na system (5)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:k-na:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 298.34–370.87 K, x(Na) 0–1	15	2
FCC_A1 phase:k-na:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	2
HCP_A3 phase:k-na:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 2 calculated diagram(s)	0	2
KNA2_C14 phase:k-na:kna2-c14	MgZn2 · C14 · hP12 · P6_3/mmc (194)	tier A: standard phase name	not stable in 2 calculated diagram(s)	15	2
LIQUID phase:k-na:liquid	liquid	liquid	stable in 2 of 2 calculated diagram(s): 298.34–2500 K, x(Na) 0–1	15	2

BCC_A2 (K–Na)

Id: phase:k-na: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): 298.34–370.87 K, x(Na) 0–1
Literature: 15 values (15 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:k-na:bcc-a2
paper: paper:10.1016/j.msea.2005.11.037:bcc (K), paper:10.1016/j.msea.2005.11.037:bcc (Na)
tdb: tdb:KNa-06Zha.tdb:BCC_A2, tdb:KNa-11Ren.tdb:BCC_A2

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

KNa-06Zha.tdb: BCC_A2, type code %B, sha256 07051d7fbcc606b0…

31: PHASE BCC_A2 %B 2 1 3 !
32: CONST BCC_A2 : K NA : VA : !

KNa-11Ren.tdb: BCC_A2, type code %B, sha256 25965ca4d96d0c6d…

30: PHASE BCC_A2 %B 2 1 3 !
31: CONST BCC_A2 : K NA : VA : !

Example references (6 of 6; assessments first):

doi:10.1016/j.msea.2005.11.037 Shengjun Zhang, Carl Brubaker, Chao Jiang, Mei Yang, Yu Zhong, Qingyou Han et al., A combined first-principles calculation and thermodynamic modeling of the F–K–Na system, Materials Science and Engineering: A 418, 161-171 (2006).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2011.06.005 Xin Ren, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic assessments of six binary systems of alkali metals, Calphad 35, 446-454 (2011).
assessment that models this phase
doi:10.1002/zaac.19020300105 N. S. Kurnakow, N. A. Puschin, Über die Schmeltztemperaturen der Legierungen des Natriums mit Kalium, Z. Anorg. Chem. 30, 109-112 (1902).
cited as the source of values for this phase
doi:10.1021/j150551a004 C. A. Krier, R. S. Craig, W. E. Wallace, Low Temperature Heat Capacities and Related Properties of Potassium and Na2K, J. Phys. Chem. 61, 522-529 (1957).
cited as the source of values for this phase
doi:10.1039/tf9696502870 J. B. Ott, J. R. Goates, D. R. Anderson, H. T. Hall, Solid-liquid phase equilibria in the sodium + potassium system, Trans. Faraday Soc. 65, 2870 (1969).
cited as the source of values for this phase
doi:10.1139/p56-045 D. K. C. MacDonald, W. B. Pearson, Lois T. Towle, AN INVESTIGATION OF THE SODIUM-POTASSIUM EQUILIBRIUM DIAGRAM, Can. J. Phys. 34, 389-394 (1956).
cited as the source of values for this phase

FCC_A1 (K–Na)

Id: phase:k-na: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 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:k-na:fcc-a1
tdb: tdb:KNa-06Zha.tdb:FCC_A1, tdb:KNa-11Ren.tdb:FCC_A1

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

KNa-06Zha.tdb: FCC_A1, type code %A, sha256 07051d7fbcc606b0…

26: PHASE FCC_A1 %A 2 1 1 !
27: CONST FCC_A1 : K NA : VA : !

KNa-11Ren.tdb: FCC_A1, type code %A, sha256 25965ca4d96d0c6d…

25: PHASE FCC_A1 %A 2 1 1 !
26: CONST FCC_A1 : K NA : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2011.06.005 Xin Ren, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic assessments of six binary systems of alkali metals, Calphad 35, 446-454 (2011).
assessment that models this phase
doi:10.1016/j.msea.2005.11.037 Shengjun Zhang, Carl Brubaker, Chao Jiang, Mei Yang, Yu Zhong, Qingyou Han et al., A combined first-principles calculation and thermodynamic modeling of the F–K–Na system, Materials Science and Engineering: A 418, 161-171 (2006).
assessment that models this phase

HCP_A3 (K–Na)

Id: phase:k-na: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:k-na:hcp-a3
tdb: tdb:KNa-06Zha.tdb:HCP_A3, tdb:KNa-11Ren.tdb:HCP_A3

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

KNa-06Zha.tdb: HCP_A3, type code %, sha256 07051d7fbcc606b0…

36: PHASE HCP_A3 % 2 1 0.5 !
37: CONST HCP_A3 : K NA : VA : !

KNa-11Ren.tdb: HCP_A3, type code %, sha256 25965ca4d96d0c6d…

35: PHASE HCP_A3 % 2 1 0.5 !
36: CONST HCP_A3 : K NA : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.calphad.2011.06.005 Xin Ren, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic assessments of six binary systems of alkali metals, Calphad 35, 446-454 (2011).
assessment that models this phase
doi:10.1016/j.msea.2005.11.037 Shengjun Zhang, Carl Brubaker, Chao Jiang, Mei Yang, Yu Zhong, Qingyou Han et al., A combined first-principles calculation and thermodynamic modeling of the F–K–Na system, Materials Science and Engineering: A 418, 161-171 (2006).
assessment that models this phase

KNA2_C14 (K–Na)

Id: phase:k-na:kna2-c14; status assigned
Structure: MgZn2 · C14 · hP12 · P6_3/mmc (194); type st:c14-mgzn2-hp12; tier A: standard phase name; confidence high
Stoichiometry: K 0.3333, Na 0.6667
Stability: not stable in 2 calculated diagram(s)
Literature: 15 values (15 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:k-na:kna2-c14
paper: paper:10.1016/j.msea.2005.11.037:KNa2
tdb: tdb:KNa-06Zha.tdb:KNA2_C14, tdb:KNa-11Ren.tdb:KNA2_C14

TDB models of KNA2_C14 (2): PHASE and CONSTITUENT statements as written

KNa-06Zha.tdb: KNA2_C14, type code %, sha256 07051d7fbcc606b0…

41: PHASE KNA2_C14 % 2 1 2 !
42: CONST KNA2_C14 : K : NA : !

KNa-11Ren.tdb: KNA2_C14, type code %, sha256 25965ca4d96d0c6d…

40: PHASE KNA2_C14 % 2 1 2 !
41: CONST KNA2_C14 : K : NA : !

Example references (6 of 6; assessments first):

doi:10.1016/j.msea.2005.11.037 Shengjun Zhang, Carl Brubaker, Chao Jiang, Mei Yang, Yu Zhong, Qingyou Han et al., A combined first-principles calculation and thermodynamic modeling of the F–K–Na system, Materials Science and Engineering: A 418, 161-171 (2006).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2011.06.005 Xin Ren, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic assessments of six binary systems of alkali metals, Calphad 35, 446-454 (2011).
assessment that models this phase
doi:10.1002/zaac.19020300105 N. S. Kurnakow, N. A. Puschin, Über die Schmeltztemperaturen der Legierungen des Natriums mit Kalium, Z. Anorg. Chem. 30, 109-112 (1902).
cited as the source of values for this phase
doi:10.1021/j150551a004 C. A. Krier, R. S. Craig, W. E. Wallace, Low Temperature Heat Capacities and Related Properties of Potassium and Na2K, J. Phys. Chem. 61, 522-529 (1957).
cited as the source of values for this phase
doi:10.1039/tf9696502870 J. B. Ott, J. R. Goates, D. R. Anderson, H. T. Hall, Solid-liquid phase equilibria in the sodium + potassium system, Trans. Faraday Soc. 65, 2870 (1969).
cited as the source of values for this phase
doi:10.1139/p56-045 D. K. C. MacDonald, W. B. Pearson, Lois T. Towle, AN INVESTIGATION OF THE SODIUM-POTASSIUM EQUILIBRIUM DIAGRAM, Can. J. Phys. 34, 389-394 (1956).
cited as the source of values for this phase

LIQUID (K–Na)

Id: phase:k-na:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 298.34–2500 K, x(Na) 0–1
Literature: 15 values (15 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:k-na:liquid
paper: paper:10.1016/j.msea.2005.11.037:Liquid
tdb: tdb:KNa-06Zha.tdb:LIQUID, tdb:KNa-11Ren.tdb:LIQUID

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

KNa-06Zha.tdb: LIQUID, type code %, sha256 07051d7fbcc606b0…

21: PHASE LIQUID:L % 1 1 !
22: CONST LIQUID:L : K NA : !

KNa-11Ren.tdb: LIQUID, type code %, sha256 25965ca4d96d0c6d…

20: PHASE LIQUID:L % 1 1 !
21: CONST LIQUID:L : K NA : !

Example references (6 of 6; assessments first):

doi:10.1016/j.msea.2005.11.037 Shengjun Zhang, Carl Brubaker, Chao Jiang, Mei Yang, Yu Zhong, Qingyou Han et al., A combined first-principles calculation and thermodynamic modeling of the F–K–Na system, Materials Science and Engineering: A 418, 161-171 (2006).
assessment that models this phase; reports values for this phase
doi:10.1016/j.calphad.2011.06.005 Xin Ren, Changrong Li, Zhenmin Du, Cuiping Guo, Thermodynamic assessments of six binary systems of alkali metals, Calphad 35, 446-454 (2011).
assessment that models this phase
doi:10.1002/zaac.19020300105 N. S. Kurnakow, N. A. Puschin, Über die Schmeltztemperaturen der Legierungen des Natriums mit Kalium, Z. Anorg. Chem. 30, 109-112 (1902).
cited as the source of values for this phase
doi:10.1021/j150551a004 C. A. Krier, R. S. Craig, W. E. Wallace, Low Temperature Heat Capacities and Related Properties of Potassium and Na2K, J. Phys. Chem. 61, 522-529 (1957).
cited as the source of values for this phase
doi:10.1039/tf9696502870 J. B. Ott, J. R. Goates, D. R. Anderson, H. T. Hall, Solid-liquid phase equilibria in the sodium + potassium system, Trans. Faraday Soc. 65, 2870 (1969).
cited as the source of values for this phase
doi:10.1139/p56-045 D. K. C. MacDonald, W. B. Pearson, Lois T. Towle, AN INVESTIGATION OF THE SODIUM-POTASSIUM EQUILIBRIUM DIAGRAM, Can. J. Phys. 34, 389-394 (1956).
cited as the source of 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). 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}
}