# Ho–Ni system

> Ho–Ni system: 149 accepted literature values (invariant reaction 71, formation 38, heat capacity / entropy / enthalpy 22, phase transition 18) and 2 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/HO-NI.html · Markdown: https://data.orchid-project.org/systems/HO-NI.md

149 accepted literature values from 3 paper(s) (experimental 41, model 94, unspecified 14); 2 calculated phase diagram(s). 4 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: [JSON](https://data.orchid-project.org/literature/systems/HO-NI.json) · [CSV](https://data.orchid-project.org/systems/HO-NI.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#HO-NI) · [interactive phase diagram](https://orchid-project.org/phase-diagrams/#HO-NI/HoNi-15Kar.json) · [phases (13)](https://data.orchid-project.org/phases/pages/HO-NI.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/HO-NI.html) · [Markdown](https://data.orchid-project.org/systems/HO-NI.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 41 |
| model | 94 |
| unspecified | 14 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 71 |
| phase transition | 18 |
| formation | 38 |
| heat capacity / entropy / enthalpy | 22 |

## Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Table: Assessments with a calculated phase diagram

| TDB file | Assessment | SHA-256 | Links |
|---|---|---|---|
| HoNi-15Kar.tdb | S. Kardellass, C. Servant, N. Selhaoui, J. Thermal Anal. Calorim., 119, 1225-34(2015). [doi:10.1007/s10973-014-4189-1](https://doi.org/10.1007/s10973-014-4189-1) | `177f346c93bb88945400851e6f44de49db5f152086d2da69dc4ed49ef84fdb43` | [viewer](https://orchid-project.org/phase-diagrams/#HO-NI/HoNi-15Kar.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/HoNi-15Kar.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/HoNi-15Kar.json) |
| HoNi-23Ye.tdb | H. Ye, M. Rong, Q. Yao, Q. Chen, J. Wang, G. Rao, H. Zhou, J. Mater. Sci., 58, 1260-92(2023). [doi:10.1007/s10853-022-08039-1](https://doi.org/10.1007/s10853-022-08039-1) | `56caf76fef5f3fb037b7307e01e3b22123d7dfe940d6b4e814088c93527497f0` | [viewer](https://orchid-project.org/phase-diagrams/#HO-NI/HoNi-23Ye.json) · [TDB](https://orchid-project.org/data/databases/sgte-binary/HoNi-23Ye.tdb) · [JSON](https://data.orchid-project.org/phase-diagrams/sgte/HoNi-23Ye.json) |

Table: Calculated three-phase invariants (model, mole fraction of the second component)

| TDB file | T (K) | Phases at the invariant |
|---|---:|---|
| HoNi-15Kar.tdb | 1592.57 | LIQUID (x(Ni) 0.75724) + HO2NI7 (x(Ni) 0.77778) + HONI5_D2D (x(Ni) 0.83333) |
| HoNi-15Kar.tdb | 1592.56 | LIQUID (x(Ni) 0.7569) + HO2NI7 (x(Ni) 0.77778) + HONI5_D2D (x(Ni) 0.83333) |
| HoNi-15Kar.tdb | 1592.56 | LIQUID (x(Ni) 0.75672) + HO2NI7 (x(Ni) 0.77778) + HONI5_D2D (x(Ni) 0.83333) |
| HoNi-15Kar.tdb | 1560.42 | LIQUID (x(Ni) 0.71286) + HONI3 (x(Ni) 0.75) + HO2NI7 (x(Ni) 0.77778) |
| HoNi-15Kar.tdb | 1560.42 | LIQUID (x(Ni) 0.71311) + HONI3 (x(Ni) 0.75) + HO2NI7 (x(Ni) 0.77778) |
| HoNi-15Kar.tdb | 1560.42 | LIQUID (x(Ni) 0.71279) + HONI3 (x(Ni) 0.75) + HO2NI7 (x(Ni) 0.77778) |
| HoNi-15Kar.tdb | 1560.42 | LIQUID (x(Ni) 0.71278) + HONI3 (x(Ni) 0.75) + HO2NI7 (x(Ni) 0.77778) |
| HoNi-15Kar.tdb | 1559.09 | HONI5_D2D (x(Ni) 0.83333) + HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.92292) |
| HoNi-15Kar.tdb | 1559.09 | HONI5_D2D (x(Ni) 0.83333) + HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.92271) |
| HoNi-15Kar.tdb | 1551.96 | HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.93105) + FCC_A1 (x(Ni) 1) |
| HoNi-15Kar.tdb | 1551.96 | HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.93096) + FCC_A1 (x(Ni) 1) |
| HoNi-15Kar.tdb | 1551.96 | HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.93097) + FCC_A1 (x(Ni) 1) |
| HoNi-15Kar.tdb | 1551.96 | HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.93107) + FCC_A1 (x(Ni) 1) |
| HoNi-15Kar.tdb | 1469.69 | LIQUID (x(Ni) 0.63998) + HONI2_C15 (x(Ni) 0.66584) + HONI3 (x(Ni) 0.75) |
| HoNi-15Kar.tdb | 1469.69 | LIQUID (x(Ni) 0.64001) + HONI2_C15 (x(Ni) 0.66584) + HONI3 (x(Ni) 0.75) |
| HoNi-15Kar.tdb | 1325.05 | HONI_B27 (x(Ni) 0.5) + LIQUID (x(Ni) 0.53581) + HONI2_C15 (x(Ni) 0.65686) |
| HoNi-15Kar.tdb | 1325.05 | HONI_B27 (x(Ni) 0.5) + LIQUID (x(Ni) 0.5358) + HONI2_C15 (x(Ni) 0.65686) |
| HoNi-15Kar.tdb | 1240.64 | LIQUID (x(Ni) 0.39227) + HO3NI2_HT (x(Ni) 0.4) + HONI_B27 (x(Ni) 0.5) |
| HoNi-15Kar.tdb | 1240.64 | LIQUID (x(Ni) 0.39232) + HO3NI2_HT (x(Ni) 0.4) + HONI_B27 (x(Ni) 0.5) |
| HoNi-15Kar.tdb | 1031 | HO3NI2_HT (x(Ni) 0.4) + HO3NI2_LT (x(Ni) 0.4) + HONI_B27 (x(Ni) 0.5) |
| HoNi-15Kar.tdb | 1031 | LIQUID (x(Ni) 0.29286) + HO3NI2_LT (x(Ni) 0.4) + HO3NI2_HT (x(Ni) 0.4) |
| HoNi-15Kar.tdb | 1031 | LIQUID (x(Ni) 0.29272) + HO3NI2_HT (x(Ni) 0.4) + HO3NI2_LT (x(Ni) 0.4) |
| HoNi-15Kar.tdb | 1018.92 | HCP_A3 (x(Ni) 2.000e-5) + HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.25684) |
| HoNi-15Kar.tdb | 1018.92 | HCP_A3 (x(Ni) 2.000e-5) + HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.25676) |
| HoNi-15Kar.tdb | 1018.92 | HCP_A3 (x(Ni) 2.000e-5) + HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.25682) |
| HoNi-15Kar.tdb | 1010.67 | HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.28186) + HO3NI2_LT (x(Ni) 0.4) |
| HoNi-15Kar.tdb | 1010.67 | HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.28202) + HO3NI2_LT (x(Ni) 0.4) |
| HoNi-15Kar.tdb | 1010.67 | HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.28178) + HO3NI2_LT (x(Ni) 0.4) |
| HoNi-23Ye.tdb | 1592.49 | LIQUID (x(Ni) 0.76803) + HO2NI7 (x(Ni) 0.77778) + HONI5_D2D (x(Ni) 0.83333) |
| HoNi-23Ye.tdb | 1592.49 | LIQUID (x(Ni) 0.76818) + HO2NI7 (x(Ni) 0.77778) + HONI5_D2D (x(Ni) 0.83333) |
| HoNi-23Ye.tdb | 1592.49 | LIQUID (x(Ni) 0.768) + HO2NI7 (x(Ni) 0.77778) + HONI5_D2D (x(Ni) 0.83333) |
| HoNi-23Ye.tdb | 1561.5 | HONI5_D2D (x(Ni) 0.83333) + HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.91482) |
| HoNi-23Ye.tdb | 1561.5 | HONI5_D2D (x(Ni) 0.83333) + HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.91465) |
| HoNi-23Ye.tdb | 1558.25 | LIQUID (x(Ni) 0.72089) + HONI3 (x(Ni) 0.75) + HO2NI7 (x(Ni) 0.77778) |
| HoNi-23Ye.tdb | 1558.25 | LIQUID (x(Ni) 0.72117) + HONI3 (x(Ni) 0.75) + HO2NI7 (x(Ni) 0.77778) |
| HoNi-23Ye.tdb | 1558.25 | LIQUID (x(Ni) 0.72084) + HONI3 (x(Ni) 0.75) + HO2NI7 (x(Ni) 0.77778) |
| HoNi-23Ye.tdb | 1557.05 | HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.92132) + FCC_A1 (x(Ni) 0.99998) |
| HoNi-23Ye.tdb | 1557.05 | HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.92142) + FCC_A1 (x(Ni) 0.99998) |
| HoNi-23Ye.tdb | 1557.05 | HO2NI17 (x(Ni) 0.89474) + LIQUID (x(Ni) 0.92142) + FCC_A1 (x(Ni) 0.99998) |
| HoNi-23Ye.tdb | 1468.09 | LIQUID (x(Ni) 0.65761) + HONI2_C15 (x(Ni) 0.66605) + HONI3 (x(Ni) 0.75) |
| HoNi-23Ye.tdb | 1468.09 | LIQUID (x(Ni) 0.6577) + HONI2_C15 (x(Ni) 0.66605) + HONI3 (x(Ni) 0.75) |
| HoNi-23Ye.tdb | 1312.3 | HONI_B27 (x(Ni) 0.5) + LIQUID (x(Ni) 0.55349) + HONI2_C15 (x(Ni) 0.65825) |
| HoNi-23Ye.tdb | 1312.3 | HONI_B27 (x(Ni) 0.5) + LIQUID (x(Ni) 0.55347) + HONI2_C15 (x(Ni) 0.65825) |
| HoNi-23Ye.tdb | 1254.17 | HO3NI2_HT (x(Ni) 0.4) + LIQUID (x(Ni) 0.40513) + HONI_B27 (x(Ni) 0.5) |
| HoNi-23Ye.tdb | 1254.16 | HO3NI2_HT (x(Ni) 0.4) + LIQUID (x(Ni) 0.40497) + HONI_B27 (x(Ni) 0.5) |
| HoNi-23Ye.tdb | 1030.24 | HO3NI2_HT (x(Ni) 0.4) + HO3NI2_LT (x(Ni) 0.4) + HONI_B27 (x(Ni) 0.5) |
| HoNi-23Ye.tdb | 1030.24 | LIQUID (x(Ni) 0.31353) + HO3NI2_LT (x(Ni) 0.4) + HO3NI2_HT (x(Ni) 0.4) |
| HoNi-23Ye.tdb | 1027.44 | HCP_A3 (x(Ni) 3.000e-5) + HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.25145) |
| HoNi-23Ye.tdb | 1027.44 | HCP_A3 (x(Ni) 3.000e-5) + HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.25141) |
| HoNi-23Ye.tdb | 1002.77 | HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.29794) + HO3NI2_LT (x(Ni) 0.4) |
| HoNi-23Ye.tdb | 1002.77 | HO3NI_D011 (x(Ni) 0.25) + LIQUID (x(Ni) 0.29805) + HO3NI2_LT (x(Ni) 0.4) |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/HO/HO-NI.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/HO/HO-NI.json) · [CALPHAD hull HoNi-15Kar](https://data.orchid-project.org/hulls/calphad-sgte/HO/HO-NI--HoNi-15Kar.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the Ho–Ni system (71)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 1747.15 | congruent melting: L -> (Ho) | (Ho): Ho 1 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 1; `ORC-QKMB7G64O3` |  |
| 1728.15 | congruent melting: L -> (Ni) | (Ni): Ho 0 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 14; `ORC-4CBUCKBSFM` |  |
| 1703 | peritectic: L + bcc(Ho) -> hcp(Ho) | L: Ni 0.02 | model | [2] Ye 2023 | Table 10, p. 22, row 1; `ORC-OEDOF23D4H` |  |
| 1643.15 | congruent melting: L -> HoNi5 | HoNi5: Ho 0.167 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 11; `ORC-QGY2L7HI77` |  |
| 1593.15 | peritectic: L + HoNi5 -> Ho7Ni2 | L: Ho 0.26; HoNi5: Ho 0.167; Ho7Ni2: Ho 0.222 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 10; `ORC-BGWAXORJVW` |  |
| 1593.15 | peritectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-LUYKQOMXWT.bbc0e0` | “Six peritectic reactions included Ho3Ni, Ho2Ni3_HT, HoNi2, HoNi3, Ho2Ni7, and Ho2Ni17 at 750, 970, 1195, 1285, 1320, and 1290 C, respectively.” |
| 1593.15 | L + HoNi5 -> Ho7Ni2 | L: Ni 0.7587; HoNi5: Ni 0.833; Ho7Ni2: Ni 0.778 | model | [1] Kardellass 2015 | Table 6, p. 7, row 22; `ORC-WJYAFN3ZO5` |  |
| 1593.15 | L + HoNi5 -> Ho7Ni2 | L: Ni 0.74; HoNi5: Ni 0.833; Ho7Ni2: Ni 0.778 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 21; `ORC-X4DEG3OTMF` |  |
| 1593 | peritectic: L + HoNi5 -> Ho2Ni7 | L: Ni 0.759; HoNi5: Ni 0.833333; Ho2Ni7: Ni 0.777778 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 26; `ORC-4MC4M2S35C` |  |
| 1593 | peritectic: L + HoNi5 -> Ho2Ni7 | HoNi5: Ni 0.833333; Ho2Ni7: Ni 0.777778 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 27; `ORC-ELAGMMP7QL` |  |
| 1590.9 | peritectic: L + HoNi5 -> Ho2Ni7 | L: Ni 0.768; HoNi5: Ni 0.833333; Ho2Ni7: Ni 0.777778 | model | [2] Ye 2023 | Table 10, p. 22, row 28; `ORC-USBO2TYTQG` |  |
| 1563.15 | peritectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-LUYKQOMXWT.557130` | “Six peritectic reactions included Ho3Ni, Ho2Ni3_HT, HoNi2, HoNi3, Ho2Ni7, and Ho2Ni17 at 750, 970, 1195, 1285, 1320, and 1290 C, respectively.” |
| 1563.15 | L + HoNi5 -> Ho17Ni2 | L: Ni 0.92; HoNi5: Ni 0.833; Ho17Ni2: Ni 0.895 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 25; `ORC-NK2HN5H5YC` |  |
| 1563.15 | L + HoNi5 -> Ho17Ni2 | L: Ni 0.9193; HoNi5: Ni 0.833; Ho17Ni2: Ni 0.895 | model | [1] Kardellass 2015 | Table 6, p. 7, row 26; `ORC-SCQORE5RXM` |  |
| 1563.15 | peritectic: L + HoNi5 -> Ho17Ni2 | L: Ho 0.08; HoNi5: Ho 0.167; Ho17Ni2: Ho 0.105 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 12; `ORC-XB34NLBJMJ` |  |
| 1563 | peritectic: L + HoNi5 -> Ho2Ni17 | HoNi5: Ni 0.833333; Ho2Ni17: Ni 0.894737 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 33; `ORC-A53TU6ORUK` |  |
| 1563 | peritectic: L + HoNi5 -> Ho2Ni17 | L: Ni 0.919; HoNi5: Ni 0.833333; Ho2Ni17: Ni 0.894737 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 32; `ORC-K6OBSA2JE5` |  |
| 1560.3 | peritectic: L + HoNi5 -> Ho2Ni17 | L: Ni 0.915; HoNi5: Ni 0.833333; Ho2Ni17: Ni 0.894737 | model | [2] Ye 2023 | Table 10, p. 22, row 34; `ORC-QOAOVPAVHR` |  |
| 1558.15 | L + Ho7Ni2 -> HoNi3 | L: Ni 0.7; Ho7Ni2: Ni 0.778; HoNi3: Ni 0.75 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 19; `ORC-F2T3LOHGZY` |  |
| 1558.15 | peritectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-LUYKQOMXWT.6b8436` | “Six peritectic reactions included Ho3Ni, Ho2Ni3_HT, HoNi2, HoNi3, Ho2Ni7, and Ho2Ni17 at 750, 970, 1195, 1285, 1320, and 1290 C, respectively.” |
| 1558.15 | L + Ho7Ni2 -> HoNi3 | L: Ni 0.7019; Ho7Ni2: Ni 0.778; HoNi3: Ni 0.75 | model | [1] Kardellass 2015 | Table 6, p. 7, row 20; `ORC-R5FCP7QAUL` |  |
| 1558.15 | peritectic: L + Ho7Ni2 -> HoNi3 | L: Ho 0.3; Ho7Ni2: Ho 0.222; HoNi3: Ho 0.25 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 9; `ORC-S2Q2BQUWIC` |  |
| 1558 | peritectic: L + Ho2Ni7 -> HoNi3 | Ho2Ni7: Ni 0.777778; HoNi3: Ni 0.75 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 24; `ORC-2Z2Z5RAQ2Y` |  |
| 1558 | peritectic: L + Ho2Ni7 -> HoNi3 | L: Ni 0.712; Ho2Ni7: Ni 0.777778; HoNi3: Ni 0.75 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 23; `ORC-NBTXYIHBOH` |  |
| 1556 | eutectic: L -> fcc(Ni) + Ho2Ni17 | L: Ni 0.921; Ho2Ni17: Ni 0.894737 | model | [2] Ye 2023 | Table 10, p. 22, row 37; `ORC-HUBHOU5RTR` |  |
| 1555.8 | peritectic: L + Ho2Ni7 -> HoNi3 | L: Ni 0.72; Ho2Ni7: Ni 0.777778; HoNi3: Ni 0.75 | model | [2] Ye 2023 | Table 10, p. 22, row 25; `ORC-FDCWJ5WVOX` |  |
| 1553.15 | eutectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-AGOERC2VB7.36911b` | “Three eutectic reactions formed between Ho3Ni and Ho2Ni3_LT at 720 C (30.0 at% Ni), between HoNi and HoNi2 at 975 C (54.0 at% Ni), and between Ho2Ni17 and Nickel at 1,280 C (93.0 at% Ni).” |
| 1553.15 | eutectic: L -> Ho17Ni2 + fcc_A1 | L: Ni 0.93; Ho17Ni2: Ni 0.895; fcc_A1: Ni 1 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 27; `ORC-LFEC2MZNKB` |  |
| 1553.15 | eutectic: L -> Ho17Ni2 + fcc_A1 | L: Ni 0.9314; Ho17Ni2: Ni 0.895; fcc_A1: Ni 1 | model | [1] Kardellass 2015 | Table 6, p. 7, row 28; `ORC-TEWACFA5LO` |  |
| 1553.15 | eutectic: L -> Ho17Ni2 + fcc_A1 | L: Ho 0.07; Ho17Ni2: Ho 0.105; fcc_A1: Ho 0 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 13; `ORC-YNNUAYCXM4` |  |
| 1553 | eutectic: L -> fcc(Ni) + Ho2Ni17 | L: Ni 0.931; Ho2Ni17: Ni 0.894737 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 35; `ORC-GQ2JOXD5NQ` |  |
| 1553 | eutectic: L -> fcc(Ni) + Ho2Ni17 | L: Ni 0.93; Ho2Ni17: Ni 0.894737 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 36; `ORC-UKLPYJDLJT` |  |
| 1468.15 | L + HoNi3 -> HoNi2 | L: Ni 0.63; HoNi3: Ni 0.75; HoNi2: Ni 0.667 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 17; `ORC-4S4NG6B7KZ` |  |
| 1468.15 | peritectic: L + HoNi3 -> HoNi2 | L: Ho 0.37; HoNi3: Ho 0.25; HoNi2: Ho 0.333 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 8; `ORC-LCAIXUG4UH` |  |
| 1468.15 | peritectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-LUYKQOMXWT.dc34a6` | “Six peritectic reactions included Ho3Ni, Ho2Ni3_HT, HoNi2, HoNi3, Ho2Ni7, and Ho2Ni17 at 750, 970, 1195, 1285, 1320, and 1290 C, respectively.” |
| 1468.15 | L + HoNi3 -> HoNi2 | L: Ni 0.64; HoNi3: Ni 0.75; HoNi2: Ni 0.667 | model | [1] Kardellass 2015 | Table 6, p. 7, row 18; `ORC-NW5MSHY6ZY` |  |
| 1468 | peritectic: L + HoNi3 -> HoNi2 | L: Ni 0.64; HoNi3: Ni 0.75; HoNi2: Ni 0.666667 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 20; `ORC-KBV72IDMI4` |  |
| 1468 | peritectic: L + HoNi3 -> HoNi2 | HoNi3: Ni 0.75; HoNi2: Ni 0.666667 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 21; `ORC-ZGHICQBYYR` |  |
| 1465.2 | peritectic: L + HoNi3 -> HoNi2 | L: Ni 0.657; HoNi3: Ni 0.75; HoNi2: Ni 0.666667 | model | [2] Ye 2023 | Table 10, p. 22, row 22; `ORC-L4NL2VCS3L` |  |
| 1333.15 | congruent melting: L -> HoNi | HoNi: Ho 0.5 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 6; `ORC-2IZOWBUSRI` |  |
| 1322.15 | eutectic: L -> HoNi + HoNi2 | L: Ni 0.5355; HoNi: Ni 0.5; HoNi2: Ni 0.659 | model | [1] Kardellass 2015 | Table 6, p. 7, row 16; `ORC-XVFZD4URLQ` |  |
| 1322 | eutectic: L -> HoNi + HoNi2 | L: Ni 0.536; HoNi: Ni 0.5; HoNi2: Ni 0.666667 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 17; `ORC-UYM3ZN4UAW` |  |
| 1308.9 | eutectic: L -> HoNi + HoNi2 | L: Ni 0.553; HoNi: Ni 0.5; HoNi2: Ni 0.666667 | model | [2] Ye 2023 | Table 10, p. 22, row 19; `ORC-EARQVM62SK` |  |
| 1248.15 | eutectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-AGOERC2VB7.0d245a` | “Three eutectic reactions formed between Ho3Ni and Ho2Ni3_LT at 720 C (30.0 at% Ni), between HoNi and HoNi2 at 975 C (54.0 at% Ni), and between Ho2Ni17 and Nickel at 1,280 C (93.0 at% Ni).” |
| 1248.15 | eutectic: L -> HoNi + HoNi2 | L: Ni 0.54; HoNi: Ni 0.5; HoNi2: Ni 0.656 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 15; `ORC-D7RYIIJ5EW` |  |
| 1248.15 | eutectic: L -> HoNi + HoNi2 | L: Ho 0.46; HoNi: Ho 0.5; HoNi2: Ho 0.344 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 7; `ORC-HB7AIUX4M3` |  |
| 1248 | eutectic: L -> HoNi + HoNi2 | L: Ni 0.54; HoNi: Ni 0.5; HoNi2: Ni 0.666667 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 18; `ORC-JXAX5NMX6V` |  |
| 1243.15 | L + HoNi -> Ho3Ni2_HT | L: Ni 0.38; HoNi: Ni 0.5; Ho3Ni2_HT: Ni 0.4 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 11; `ORC-E4TT5BS24J` |  |
| 1243.15 | peritectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-LUYKQOMXWT.b65086` | “Six peritectic reactions included Ho3Ni, Ho2Ni3_HT, HoNi2, HoNi3, Ho2Ni7, and Ho2Ni17 at 750, 970, 1195, 1285, 1320, and 1290 C, respectively.” |
| 1243.15 | peritectic: L + HoNi -> Ho3Ni2_HT | L: Ho 0.62; HoNi: Ho 0.5; Ho3Ni2_HT: Ho 0.6 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 4; `ORC-MUD2XM3BZT` |  |
| 1243 | peritectic: L + HoNi -> Ho3Ni2_HT | HoNi: Ni 0.5; Ho3Ni2_HT: Ni 0.4 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 12; `ORC-I5NC7DOGQP` |  |
| 1241.15 | L + HoNi -> Ho3Ni2_HT | L: Ni 0.3944; HoNi: Ni 0.5; Ho3Ni2_HT: Ni 0.4 | model | [1] Kardellass 2015 | Table 6, p. 7, row 12; `ORC-DXEBYCEI2L` |  |
| 1241 | peritectic: L + HoNi -> Ho3Ni2_HT | L: Ni 0.394; HoNi: Ni 0.5; Ho3Ni2_HT: Ni 0.4 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 11; `ORC-MJSUJM6F7W` |  |
| 1240.4 | peritectic: L + HoNi -> Ho3Ni2_HT | L: Ni 0.399; HoNi: Ni 0.5; Ho3Ni2_HT: Ni 0.4 | model | [2] Ye 2023 | Table 10, p. 22, row 13; `ORC-GPEO7F6XB7` |  |
| 1033.15 | L + HoNi -> Ho3Ni2_LT | L: Ni 0.31; HoNi: Ni 0.5; Ho3Ni2_LT: Ni 0.4 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 9; `ORC-7TRMHGG7PR` |  |
| 1033.15 | polymorphic: Ho3Ni2_HT -> Ho3Ni2_LT | Ho3Ni2_HT: Ho 0.6; Ho3Ni2_LT: Ho 0.6, Ni 0.4 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 5; `ORC-XNR57AXYQF` |  |
| 1031.15 | L + HoNi -> Ho3Ni2_LT | L: Ni 0.2951; HoNi: Ni 0.5; Ho3Ni2_LT: Ni 0.4 | model | [1] Kardellass 2015 | Table 6, p. 7, row 10; `ORC-PKQUJOPYYX` |  |
| 1023.15 | L + Ho -> Ho3Ni | L: Ni 0.29; Ho: Ni 0; Ho3Ni: Ni 0.25 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 3; `ORC-JN7IFDYOL3` |  |
| 1023.15 | peritectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-LUYKQOMXWT.8555df` | “Six peritectic reactions included Ho3Ni, Ho2Ni3_HT, HoNi2, HoNi3, Ho2Ni7, and Ho2Ni17 at 750, 970, 1195, 1285, 1320, and 1290 C, respectively.” |
| 1023.15 | peritectic: L + Ho -> Ho3Ni | L: Ho 0.71; Ho: Ho 1; Ho3Ni: Ho 0.75 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 2; `ORC-XOQQTT3BW4` |  |
| 1023 | peritectic: L + hcp(Ho) -> Ho3Ni | L: Ni 0.3; Ho3Ni: Ni 0.25 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 3; `ORC-AMDUT4GMJG` |  |
| 1020.2 | peritectic: L + hcp(Ho) -> Ho3Ni | L: Ni 0.251; Ho3Ni: Ni 0.25 | model | [2] Ye 2023 | Table 10, p. 22, row 4; `ORC-CARO5GYUCM` |  |
| 1014.15 | L + Ho -> Ho3Ni | L: Ni 0.2563; Ho: Ni 0; Ho3Ni: Ni 0.25 | model | [1] Kardellass 2015 | Table 6, p. 7, row 4; `ORC-OZMDXBTRSJ` |  |
| 1014 | peritectic: L + hcp(Ho) -> Ho3Ni | L: Ni 0.256; Ho3Ni: Ni 0.25 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 2; `ORC-L6QCOW6VBI` |  |
| 1006.15 | eutectic: L -> Ho3Ni + Ho3Ni2_LT | L: Ni 0.2813; Ho3Ni: Ni 0.25; Ho3Ni2_LT: Ni 0.4 | model | [1] Kardellass 2015 | Table 6, p. 7, row 6; `ORC-PARZK2XVRR` |  |
| 1006 | eutectic: L -> Ho3Ni + Ho3Ni2_LT | L: Ni 0.281; Ho3Ni: Ni 0.25; Ho3Ni2_LT: Ni 0.4 | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 5; `ORC-BGNXHDNO6F` |  |
| 996.3 | eutectic: L -> Ho3Ni + Ho3Ni2_LT | L: Ni 0.297; Ho3Ni: Ni 0.25; Ho3Ni2_LT: Ni 0.4 | model | [2] Ye 2023 | Table 10, p. 22, row 7; `ORC-FNGVK4X6YE` |  |
| 993.15 | eutectic: L -> Ho3Ni + Ho3Ni2_LT | L: Ho 0.7; Ho3Ni: Ho 0.75; Ho3Ni2_LT: Ho 0.6 | unspecified | [1] Kardellass 2015 | Table 2, p. 3, row 3; `ORC-5GPABUT5HN` |  |
| 993.15 | eutectic |  | experimental | [1] Kardellass 2015 | p. 2; `ORC-AGOERC2VB7.6d9448` | “Three eutectic reactions formed between Ho3Ni and Ho2Ni3_LT at 720 C (30.0 at% Ni), between HoNi and HoNi2 at 975 C (54.0 at% Ni), and between Ho2Ni17 and Nickel at 1,280 C (93.0 at% Ni).” |
| 993.15 | eutectic: L -> Ho3Ni + Ho3Ni2_LT | L: Ni 0.3; Ho3Ni: Ni 0.25; Ho3Ni2_LT: Ni 0.4 | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 5; `ORC-J2FQQVAPSX` |  |
| 993 | eutectic: L -> Ho3Ni + Ho3Ni2_LT | Ho3Ni: Ni 0.25; Ho3Ni2_LT: Ni 0.4 | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 6; `ORC-KAAGTRJ6HE` |  |

## Formation enthalpies

Literature values in kJ/mol-atom where the per-atom basis is known. DFT columns: the lowest-energy entry at the same composition (Materials Project 2026.04.13, OQMD v1.8; different energy references, never averaged), from [dft_parity.json](https://data.orchid-project.org/literature/dft_parity.json).

Table: Enthalpies of formation, Ho–Ni system (38)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| Ho2Ni17 | [Ho2Ni17](https://data.orchid-project.org/compounds/Ho2Ni17.html) | -23.1 kJ/mol-atom ± 0.3 | 650 | experimental | -19.799 (mp-aaacqkjz) | -20.143 (oqmd-30551) | [1] Kardellass 2015; _cites Gozzi 2005_ [doi](https://doi.org/10.1016/j.intermet.2005.03.002) | Table 3, p. 4, row 32; `ORC-CIBLIAIPZV.362249` |  |
| Ho2Ni17 | [Ho2Ni17](https://data.orchid-project.org/compounds/Ho2Ni17.html) | -21.33 kJ/mol-atom | 298.15 | model | -19.799 (mp-aaacqkjz) | -20.143 (oqmd-30551) | [1] Kardellass 2015 | Table 3, p. 4, row 33; `ORC-4EKSADAPCN.24065b` |  |
| Ho2Ni17 | [Ho2Ni17](https://data.orchid-project.org/compounds/Ho2Ni17.html) | -16 kJ/mol-atom | 298.15 | model | -19.799 (mp-aaacqkjz) | -20.143 (oqmd-30551) | [1] Kardellass 2015; _cites Kayzel 1995_ | Table 3, p. 4, row 34; `ORC-PHKVNW3XCH.1fad5d` |  |
| Ho2Ni17 | [Ho2Ni17](https://data.orchid-project.org/compounds/Ho2Ni17.html) | -16 kJ/mol-atom | 298.15 | model | -19.799 (mp-aaacqkjz) | -20.143 (oqmd-30551) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 31; `ORC-QWGKIZRAMB.79442e` |  |
| Ho2Ni7 | [Ho2Ni7](https://data.orchid-project.org/compounds/Ho2Ni7.html) | -40 kJ/mol-atom | 298.15 | model | -38.648 (mp-aaacpsuu) | -39.098 (oqmd-1483994) | [1] Kardellass 2015 | Table 3, p. 4, row 24; `ORC-VJCN63SFEL.e5027d` |  |
| Ho2Ni7 | [Ho2Ni7](https://data.orchid-project.org/compounds/Ho2Ni7.html) | -39.92 kJ/mol-atom | 298.15 | model | -38.648 (mp-aaacpsuu) | -39.098 (oqmd-1483994) | [1] Kardellass 2015 | Table 3, p. 4, row 25; `ORC-WVJV7M4Z6B.1fd85a` |  |
| Ho2Ni7 | [Ho2Ni7](https://data.orchid-project.org/compounds/Ho2Ni7.html) | -35 kJ/mol-atom | 298.15 | model | -38.648 (mp-aaacpsuu) | -39.098 (oqmd-1483994) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 23; `ORC-Y2LL7I4JOT.b3ef01` |  |
| Ho2Ni7 | [Ho2Ni7](https://data.orchid-project.org/compounds/Ho2Ni7.html) | -34 kJ/mol-atom | 298.15 | model | -38.648 (mp-aaacpsuu) | -39.098 (oqmd-1483994) | [1] Kardellass 2015; _cites Kayzel 1995_ | Table 3, p. 4, row 26; `ORC-FNIWTCE4PX.6c8d7f` |  |
| Ho3Ni | [Ho3Ni](https://data.orchid-project.org/compounds/Ho3Ni.html) | -38 kJ/mol-atom | 298.15 | model | -24.74 (mp-aaacprea) | -25.183 (oqmd-30550) | [1] Kardellass 2015 | Table 3, p. 4, row 2; `ORC-PRSXIABCGK.101a10` |  |
| Ho3Ni | [Ho3Ni](https://data.orchid-project.org/compounds/Ho3Ni.html) | -25 kJ/mol-atom | 298.15 | model | -24.74 (mp-aaacprea) | -25.183 (oqmd-30550) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 1; `ORC-FAK4XSBAOV.9eea96` |  |
| Ho3Ni | [Ho3Ni](https://data.orchid-project.org/compounds/Ho3Ni.html) | -24 kJ/mol-atom | 298.15 | model | -24.74 (mp-aaacprea) | -25.183 (oqmd-30550) | [1] Kardellass 2015; _cites Kayzel 1995_ | Table 3, p. 4, row 4; `ORC-TOSUODAY33.152f3b` |  |
| Ho3Ni | [Ho3Ni](https://data.orchid-project.org/compounds/Ho3Ni.html) | -23.95 kJ/mol-atom | 298.15 | model | -24.74 (mp-aaacprea) | -25.183 (oqmd-30550) | [1] Kardellass 2015 | Table 3, p. 4, row 3; `ORC-PEUZNTZ35W.0de60d` |  |
| Ho3Ni2_HT | [Ho3Ni2](https://data.orchid-project.org/compounds/Ho3Ni2.html) | -28.34 kJ/mol-atom | 298.15 | model | -36.512 (mp-aaacjmkp) | -37.585 (oqmd-30549) | [1] Kardellass 2015 | Table 3, p. 4, row 9; `ORC-U2SOP75IJQ.361cd0` |  |
| Ho3Ni2_LT | [Ho3Ni2](https://data.orchid-project.org/compounds/Ho3Ni2.html) | -47 kJ/mol-atom | 298.15 | model | -36.512 (mp-aaacjmkp) | -37.585 (oqmd-30549) | [1] Kardellass 2015 | Table 3, p. 4, row 6; `ORC-GHBPJQM4XH.6b0426` |  |
| Ho3Ni2_LT | [Ho3Ni2](https://data.orchid-project.org/compounds/Ho3Ni2.html) | -40 kJ/mol-atom | 298.15 | model | -36.512 (mp-aaacjmkp) | -37.585 (oqmd-30549) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 5; `ORC-JUT4IUDSS4.1e9152` |  |
| Ho3Ni2_LT | [Ho3Ni2](https://data.orchid-project.org/compounds/Ho3Ni2.html) | -38.45 kJ/mol-atom | 298.15 | model | -36.512 (mp-aaacjmkp) | -37.585 (oqmd-30549) | [1] Kardellass 2015 | Table 3, p. 4, row 7; `ORC-KOSAEYIXBG.aebddf` |  |
| Ho3Ni2_LT | [Ho3Ni2](https://data.orchid-project.org/compounds/Ho3Ni2.html) | -38 kJ/mol-atom | 298.15 | model | -36.512 (mp-aaacjmkp) | -37.585 (oqmd-30549) | [1] Kardellass 2015; _cites Kayzel 1995_ | Table 3, p. 4, row 8; `ORC-TQIIAZJF74.15f2cf` |  |
| HoNi | [HoNi](https://data.orchid-project.org/compounds/HoNi.html) | -48.8 kJ/mol-atom | 298.15 | model | -45.179 (mp-aaaaarop) | -45.907 (oqmd-18379) | [1] Kardellass 2015 | Table 3, p. 4, row 13; `ORC-7L2GDTIKOR.1d9de5` |  |
| HoNi | [HoNi](https://data.orchid-project.org/compounds/HoNi.html) | -48.6 kJ/mol-atom ± 0.77 | 1476 | experimental | -45.179 (mp-aaaaarop) | -45.907 (oqmd-18379) | [1] Kardellass 2015; _cites Gozzi 2005_ [doi](https://doi.org/10.1016/j.intermet.2005.03.002) | Table 3, p. 4, row 12; `ORC-6FIHIYYN7M.5d1f54` |  |
| HoNi | [HoNi](https://data.orchid-project.org/compounds/HoNi.html) | -48.23 kJ/mol-atom | 298.15 | model | -45.179 (mp-aaaaarop) | -45.907 (oqmd-18379) | [1] Kardellass 2015 | Table 3, p. 4, row 14; `ORC-E3ZO53RNRF.0f0ad3` |  |
| HoNi | [HoNi](https://data.orchid-project.org/compounds/HoNi.html) | -45 kJ/mol-atom | 298.15 | model | -45.179 (mp-aaaaarop) | -45.907 (oqmd-18379) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 10; `ORC-2CHTIF7I25.3d676d` |  |
| HoNi | [HoNi](https://data.orchid-project.org/compounds/HoNi.html) | -41.7 kJ/mol-atom ± 1.4 | 1476 | experimental | -45.179 (mp-aaaaarop) | -45.907 (oqmd-18379) | [1] Kardellass 2015; _cites Guo 1998_ [doi](https://doi.org/10.1016/s0925-8388%2898%2900509-x) | Table 3, p. 4, row 11; `ORC-45RKMHXPOP.7fe6a3` |  |
| HoNi2 | [HoNi2](https://data.orchid-project.org/compounds/HoNi2.html) | -47.5 kJ/mol-atom | 298.15 | model | -44.81 (mp-aaaaaazx) | -44.977 (oqmd-17463) | [1] Kardellass 2015 | Table 3, p. 4, row 16; `ORC-EGNRTAMU57.949741` |  |
| HoNi2 | [HoNi2](https://data.orchid-project.org/compounds/HoNi2.html) | -45 kJ/mol-atom | 298.15 | model | -44.81 (mp-aaaaaazx) | -44.977 (oqmd-17463) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 15; `ORC-7JFP5JEQBC.29cd02` |  |
| HoNi2 | [HoNi2](https://data.orchid-project.org/compounds/HoNi2.html) | -45 kJ/mol-atom | 298.15 | model | -44.81 (mp-aaaaaazx) | -44.977 (oqmd-17463) | [1] Kardellass 2015; _cites Kayzel 1995_ | Table 3, p. 4, row 18; `ORC-7PEHHCQ4W2.cee686` |  |
| HoNi2 | [HoNi2](https://data.orchid-project.org/compounds/HoNi2.html) | -42.67 kJ/mol-atom | 298.15 | model | -44.81 (mp-aaaaaazx) | -44.977 (oqmd-17463) | [1] Kardellass 2015 | Table 3, p. 4, row 17; `ORC-PEMOQUEAL5.6a50d4` |  |
| HoNi3 | [HoNi3](https://data.orchid-project.org/compounds/HoNi3.html) | -42.5 kJ/mol-atom | 298.15 | model | -41.055 (mp-aaaaadao) | -41.425 (oqmd-19842) | [1] Kardellass 2015 | Table 3, p. 4, row 20; `ORC-3V5AG6DYXO.0db808` |  |
| HoNi3 | [HoNi3](https://data.orchid-project.org/compounds/HoNi3.html) | -40.01 kJ/mol-atom | 298.15 | model | -41.055 (mp-aaaaadao) | -41.425 (oqmd-19842) | [1] Kardellass 2015 | Table 3, p. 4, row 21; `ORC-Q3DAXC6QZG.123a29` |  |
| HoNi3 | [HoNi3](https://data.orchid-project.org/compounds/HoNi3.html) | -37 kJ/mol-atom | 298.15 | model | -41.055 (mp-aaaaadao) | -41.425 (oqmd-19842) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 19; `ORC-7SH5L67NG5.23ce05` |  |
| HoNi3 | [HoNi3](https://data.orchid-project.org/compounds/HoNi3.html) | -37 kJ/mol-atom | 298.15 | model | -41.055 (mp-aaaaadao) | -41.425 (oqmd-19842) | [1] Kardellass 2015; _cites Kayzel 1995_ | Table 3, p. 4, row 22; `ORC-XJ4N6N5DMP.8e8a22` |  |
| HoNi5 | [HoNi5](https://data.orchid-project.org/compounds/HoNi5.html) | -35.49 kJ/mol-atom ± 0.04 | 1476 | experimental | -32.138 (mp-aaaaacht) | -32.728 (oqmd-17464) | [1] Kardellass 2015; _cites Guo 1998_ [doi](https://doi.org/10.1016/s0925-8388%2898%2900509-x) | Table 3, p. 4, row 29; `ORC-OMEEBS7VNA.70d585` |  |
| HoNi5 | [HoNi5](https://data.orchid-project.org/compounds/HoNi5.html) | -34.04 kJ/mol-atom | 298.15 | model | -32.138 (mp-aaaaacht) | -32.728 (oqmd-17464) | [1] Kardellass 2015 | Table 3, p. 4, row 30; `ORC-JDP33X5EGQ.04513d` |  |
| HoNi5 | [HoNi5](https://data.orchid-project.org/compounds/HoNi5.html) | -29.9 kJ/mol-atom ± 0.8 | 1474 | experimental | -32.138 (mp-aaaaacht) | -32.728 (oqmd-17464) | [1] Kardellass 2015; _cites Pot 1993_ | Table 3, p. 4, row 28; `ORC-UTYLURSU47.0df886` |  |
| HoNi5 | [HoNi5](https://data.orchid-project.org/compounds/HoNi5.html) | -26 kJ/mol-atom | 298.15 | model | -32.138 (mp-aaaaacht) | -32.728 (oqmd-17464) | [1] Kardellass 2015; _cites de Boer FR 1989_ | Table 3, p. 4, row 27; `ORC-F3DNY7EVJE.3073d2` |  |
| Ni17Ho2 | [Ho2Ni17](https://data.orchid-project.org/compounds/Ho2Ni17.html) | -21.33 kJ/mol-atom | 298.15 | model | -19.799 (mp-aaacqkjz) | -20.143 (oqmd-30551) | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 2; `ORC-5MH6AGPYFB.48da02` |  |
| Ni2Ho | [HoNi2](https://data.orchid-project.org/compounds/HoNi2.html) | -42.67 kJ/mol-atom | 298.15 | model | -44.81 (mp-aaaaaazx) | -44.977 (oqmd-17463) | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 9; `ORC-6XXUWSIKZE.0cd33e` |  |
| Ni5Ho | [HoNi5](https://data.orchid-project.org/compounds/HoNi5.html) | -34.04 kJ/mol-atom | 298.15 | model | -32.138 (mp-aaaaacht) | -32.728 (oqmd-17464) | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 5; `ORC-CK7FAJ7YVX.cfbece` |  |
| NiHo | [HoNi](https://data.orchid-project.org/compounds/HoNi.html) | -48.23 kJ/mol-atom | 298.15 | model | -45.179 (mp-aaaaarop) | -45.907 (oqmd-18379) | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 13; `ORC-RRZYT2JSOR.ba40d6` |  |

## Other properties

### Phase transition (18)

Table: Phase transition, Ho–Ni system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Phase transition | 1030.2 K | 1030.2 | polymorphic: Ho3Ni2_HT -> Ho3Ni2_LT; _Ho3Ni2_HT: Ni 0.4; Ho3Ni2_LT: Ni 0.4_ | model | [2] Ye 2023 | Table 10, p. 22, row 10; `ORC-JTD7USR7KI` |  |
| Phase transition | 1031 K | 1031 | polymorphic: Ho3Ni2_HT -> Ho3Ni2_LT; _Ho3Ni2_HT: Ni 0.4; Ho3Ni2_LT: Ni 0.4_ | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 8; `ORC-AFVQWOPLZZ` |  |
| Phase transition | 1031.15 K | 1031.15 | Ho3Ni2_HT -> Ho3Ni2_LT; _Ho3Ni2_HT: Ni 0.4; Ho3Ni2_LT: Ni 0.4_ | model | [1] Kardellass 2015 | Table 6, p. 7, row 8; `ORC-G2E2U6M332` |  |
| Phase transition | 1033 K | 1033 | polymorphic: Ho3Ni2_HT -> Ho3Ni2_LT; _Ho3Ni2_HT: Ni 0.4; Ho3Ni2_LT: Ni 0.4_ | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 9; `ORC-ILKEBSJKX7` |  |
| Phase transition | 1033.15 K | 1033.15 | Ho3Ni2_HT -> Ho3Ni2_LT; _Ho3Ni2_HT: Ni 0.4; Ho3Ni2_LT: Ni 0.4_ | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 7; `ORC-RB4OPWP7U4` |  |
| Phase transition | 1333 K | 1333 | congruent melting: L -> HoNi; _L: Ni 0.5; HoNi: Ni 0.5_ | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 14; `ORC-HLWWJ5T54U` |  |
| Phase transition | 1333 K | 1333 | congruent melting: L -> HoNi; _L: Ni 0.5; HoNi: Ni 0.5_ | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 15; `ORC-LA6WUJRIYQ` |  |
| Phase transition | 1333.15 K | 1333.15 | L -> HoNi; _L: Ni 0.5; HoNi: Ni 0.5_ | model | [1] Kardellass 2015 | Table 6, p. 7, row 14; `ORC-F6AZZMMHZT` |  |
| Phase transition | 1333.15 K | 1333.15 | L -> HoNi; _L: Ni 0.5; HoNi: Ni 0.5_ | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 13; `ORC-S6K52JV7JH` |  |
| Phase transition | 1338 K | 1338 | congruent melting: L -> HoNi; _L: Ni 0.5; HoNi: Ni 0.5_ | model | [2] Ye 2023 | Table 10, p. 22, row 16; `ORC-JNJVPW7JZF` |  |
| Phase transition | 1638.2 K | 1638.2 | congruent melting: L -> HoNi5; _L: Ni 0.833; HoNi5: Ni 0.833333_ | model | [2] Ye 2023 | Table 10, p. 22, row 31; `ORC-EKHOU5SWZY` |  |
| Phase transition | 1643 K | 1643 | congruent melting: L -> HoNi5; _L: Ni 0.833; HoNi5: Ni 0.833333_ | experimental | [2] Ye 2023; _cites ref. 45_ | Table 10, p. 22, row 30; `ORC-57ABHHNF5B` |  |
| Phase transition | 1643 K | 1643 | congruent melting: L -> HoNi5; _L: Ni 0.833; HoNi5: Ni 0.833333_ | model | [2] Ye 2023; _cites ref. 40_ | Table 10, p. 22, row 29; `ORC-BWEC2S5VQV` |  |
| Phase transition | 1643.15 K | 1643.15 | L -> HoNi5; _L: Ni 0.833; HoNi5: Ni 0.833_ | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 23; `ORC-AT53YUOWPL` |  |
| Phase transition | 1643.15 K | 1643.15 | L -> HoNi5; _L: Ni 0.833; HoNi5: Ni 0.833_ | model | [1] Kardellass 2015 | Table 6, p. 7, row 24; `ORC-BAT2HY6TSN` |  |
| Phase transition | 1643.15 K | 1643.15 | congruent transformation | experimental | [1] Kardellass 2015 | p. 2; `ORC-RD4LY252ZK` | “Two congruent meltings for HoNi and HoNi5 at 1,060 and 1,370 C.” |
| Phase transition | 1747.15 K | 1747.15 | L -> (Ho); _L: Ni 0; (Ho): Ni 0_ | model | [1] Kardellass 2015 | Table 6, p. 7, row 2; `ORC-JXSRGN4VIV` |  |
| Phase transition | 1747.15 K | 1747.15 | L -> (Ho); _L: Ni 0; (Ho): Ni 0_ | experimental | [1] Kardellass 2015 | Table 6, p. 7, row 1; `ORC-YRYOWDCEKD` |  |

### Heat capacity / entropy / enthalpy (22)

Table: Heat capacity / entropy / enthalpy, Ho–Ni system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Entropy; _printed: Entropy of formation_ | 33.56 J/mol-atom/K | 298.15 | Ho2Ni17; _alloy: Ni 0.894737_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 33; `ORC-4EKSADAPCN.662190` |  |
| Entropy; _printed: Entropy of formation_ | 36.3 J/mol-atom/K | 298.15 | Ho2Ni7; _alloy: Ni 0.777778_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 25; `ORC-WVJV7M4Z6B.00ac6f` |  |
| Entropy; _printed: Entropy of formation_ | 59.24 J/mol-atom/K | 298.15 | Ho3Ni; _alloy: Ni 0.25_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 3; `ORC-PEUZNTZ35W.4e4ad4` |  |
| Entropy; _printed: Entropy of formation_ | 63.25 J/mol-atom/K | 298.15 | Ho3Ni2_HT; _alloy: Ni 0.4_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 9; `ORC-U2SOP75IJQ.49f7ea` |  |
| Entropy; _printed: Entropy of formation_ | 53.31 J/mol-atom/K | 298.15 | Ho3Ni2_LT; _alloy: Ni 0.4_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 7; `ORC-KOSAEYIXBG.3e618d` |  |
| Entropy; _printed: Entropy of formation_ | 46.21 J/mol-atom/K | 298.15 | HoNi; _alloy: Ni 0.5_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 14; `ORC-E3ZO53RNRF.1fb2a3` |  |
| Entropy; _printed: Entropy of formation_ | 42.32 J/mol-atom/K | 298.15 | HoNi2; _alloy: Ni 0.666667_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 17; `ORC-PEMOQUEAL5.9a3033` |  |
| Entropy; _printed: Entropy of formation_ | 38.16 J/mol-atom/K | 298.15 | HoNi3; _alloy: Ni 0.75_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 21; `ORC-Q3DAXC6QZG.6b2306` |  |
| Entropy; _printed: Entropy of formation_ | 34.27 J/mol-atom/K | 298.15 | HoNi5; _alloy: Ni 0.833333_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 30; `ORC-JDP33X5EGQ.05dec4` |  |
| Entropy; _printed: Entropies of formation_ | 33.56 J/mol-atom/K | 298.15 | Ni17Ho2; _alloy: Ho 0.105263, Ni 0.894737_ | model | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 2; `ORC-5MH6AGPYFB.04c0e1` |  |
| Entropy; _printed: Entropies of formation_ | 42.32 J/mol-atom/K | 298.15 | Ni2Ho; _alloy: Ho 0.333333, Ni 0.666667_ | model | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 9; `ORC-6XXUWSIKZE.105cc7` |  |
| Entropy; _printed: Entropies of formation_ | 34.27 J/mol-atom/K | 298.15 | Ni5Ho; _alloy: Ho 0.166667, Ni 0.833333_ | model | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 5; `ORC-CK7FAJ7YVX.9cdc2b` |  |
| Entropy; _printed: Entropies of formation_ | 46.21 J/mol-atom/K | 298.15 | NiHo; _alloy: Ho 0.5, Ni 0.5_ | model | [3] Kardellass 2016; _cites Kardellass 2015_ [doi](https://doi.org/10.1007/s10973-014-4189-1) | Table 4, p. 7, row 13; `ORC-RRZYT2JSOR.dc29fa` |  |
| Heat capacity | 25.21 J/mol-atom/K | 298.15 | Ho2Ni17; _alloy: Ni 0.894737_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 33; `ORC-4EKSADAPCN.44be60` |  |
| Heat capacity | 25.46 J/mol-atom/K | 298.15 | Ho2Ni7; _alloy: Ni 0.777778_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 25; `ORC-WVJV7M4Z6B.6ad2ba` |  |
| Heat capacity | 26.61 J/mol-atom/K | 298.15 | Ho3Ni; _alloy: Ni 0.25_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 3; `ORC-PEUZNTZ35W.610016` |  |
| Heat capacity | 25.85 J/mol-atom/K | 298.15 | Ho3Ni2_HT; _alloy: Ni 0.4_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 9; `ORC-U2SOP75IJQ.06bf7c` |  |
| Heat capacity | 26.28 J/mol-atom/K | 298.15 | Ho3Ni2_LT; _alloy: Ni 0.4_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 7; `ORC-KOSAEYIXBG.b85c98` |  |
| Heat capacity | 26.07 J/mol-atom/K | 298.15 | HoNi; _alloy: Ni 0.5_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 14; `ORC-E3ZO53RNRF.2e7881` |  |
| Heat capacity | 25.71 J/mol-atom/K | 298.15 | HoNi2; _alloy: Ni 0.666667_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 17; `ORC-PEMOQUEAL5.49f19d` |  |
| Heat capacity | 25.52 J/mol-atom/K | 298.15 | HoNi3; _alloy: Ni 0.75_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 21; `ORC-Q3DAXC6QZG.5ca1d3` |  |
| Heat capacity | 25.34 J/mol-atom/K | 298.15 | HoNi5; _alloy: Ni 0.833333_ | model | [1] Kardellass 2015 | Table 3, p. 4, row 30; `ORC-JDP33X5EGQ.5bec51` |  |

## Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

1. S. Kardellass, C. Servant, N. Selhaoui, Thermodynamic description of the holmium–nickel system, J Therm Anal Calorim 119, 1225-1234 (2015). [doi:10.1007/s10973-014-4189-1](https://doi.org/10.1007/s10973-014-4189-1)
2. Hongjian Ye, Maohua Rong, Qingrong Yao, Qing Chen, Jiang Wang, Guanghui Rao et al., Phase equilibria and thermodynamic properties in the RE-Ni (RE = rare earth metals) binary systems, J Mater Sci 58, 1260-1292 (2023). [doi:10.1007/s10853-022-08039-1](https://doi.org/10.1007/s10853-022-08039-1)
3. Saïd Kardellass, Colette Servant, Najim Selhaoui, Thermodynamic description of the Ni–Yb and Ni–Eu binary systems, J Therm Anal Calorim 125, 255-269 (2016). [doi:10.1007/s10973-016-5380-3](https://doi.org/10.1007/s10973-016-5380-3)

## Please cite

- R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/10.5281/zenodo.23735569
- R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). https://doi.org/10.5281/zenodo.23735859
- R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). https://doi.org/10.5281/zenodo.23735891
- 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 the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); 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).

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_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@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 ORCHID ([CITATION.cff](https://data.orchid-project.org/CITATION.cff)) and the original sources. Quotes are short excerpts kept so that each value can be checked; they remain under the publishers' copyright and are not relicensed. Source papers, page images and full text are not redistributed. Field reference: [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md). Machine-readable guide: [llms.txt](https://data.orchid-project.org/llms.txt). Found an error? The report link of a value (Markdown: its id, ORC-..., in the Location column) opens a pre-filled GitHub issue, https://github.com/orchid-calphad/orchid-data/issues/new?template=report-value-error.yml&record_id=\<id>, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).