# H–Zr system

> H–Zr system: 115 accepted literature values (activity / EMF / Gibbs energy 50, crystal structure 46, formation 17, invariant reaction 2) and 0 calculated phase diagram(s) from ORCHID, each value with evidence class, source, page and quote.

HTML: https://data.orchid-project.org/systems/H-ZR.html · Markdown: https://data.orchid-project.org/systems/H-ZR.md

115 accepted literature values from 3 paper(s) (experimental 1, model 65, DFT 49); 0 calculated phase diagram(s). 1 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/H-ZR.json) · [CSV](https://data.orchid-project.org/systems/H-ZR.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#H-ZR) · [phases (9)](https://data.orchid-project.org/phases/pages/H-ZR.html) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/H-ZR.html) · [Markdown](https://data.orchid-project.org/systems/H-ZR.md)

Table: Accepted values by evidence class

| Evidence class | Values |
|---|---:|
| experimental | 1 |
| model | 65 |
| DFT | 49 |

Table: Accepted values by property group

| Property group | Values |
|---|---:|
| invariant reaction | 2 |
| formation | 17 |
| activity / EMF / Gibbs energy | 50 |
| crystal structure | 46 |

Convex hulls: [Materials Project DFT hull](https://data.orchid-project.org/hulls/dft-mp/H/H-ZR.json) · [OQMD DFT hull](https://data.orchid-project.org/hulls/dft-oqmd/H/H-ZR.json) · [CALPHAD hull ZrH-00Koe](https://data.orchid-project.org/hulls/calphad-sgte/H/H-ZR--ZrH-00Koe.json) · [CALPHAD hull ZrH-07Uki](https://data.orchid-project.org/hulls/calphad-sgte/H/H-ZR--ZrH-07Uki.json) · [CALPHAD hull ZrH-97Ans-LB](https://data.orchid-project.org/hulls/calphad-sgte/H/H-ZR--ZrH-97Ans-LB.json) · [CALPHAD hull ZrH-99Dup](https://data.orchid-project.org/hulls/calphad-sgte/H/H-ZR--ZrH-99Dup.json)

## Invariant reactions (literature)

Table: Invariant reactions reported in the literature for the H–Zr system (2)

| T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote |
|---:|---|---|---|---|---|---|
| 820 | eutectoid: bcc -> hcp + fcc | bcc: Zr 0.625; hcp: Zr 0.941; fcc: Zr 0.433 | experimental | [1] Königsberger 2000; _cites Zuzek 1990_ [doi](https://doi.org/10.1007/bf02843318) | Table 3, p. 2, row 2; `ORC-HE45HTNXDJ` |  |
| 818.31 | eutectoid: bcc -> hcp + fcc | bcc: Zr 0.673; hcp: Zr 0.942; fcc: Zr 0.426 | model | [1] Königsberger 2000 | Table 3, p. 2, row 1; `ORC-QHT6OOFQK3` |  |

## 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, H–Zr system (17)

| Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote |
|---|---|---:|---:|---|---:|---:|---|---|---|
| α |  | -28 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 57; `ORC-JWYYPA6QTB` |  |
| α |  | -19.58 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 55; `ORC-TKVTSG25GD` |  |
| α |  | -10.18 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 54; `ORC-PBFLP362KZ` |  |
| α |  | -3.543 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 59; `ORC-RKWC63IT7A` |  |
| β |  | -54.2 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 63; `ORC-Q4PJWQGF7Y` |  |
| β |  | -40.7 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 62; `ORC-WDZVJF6RMR` |  |
| β |  | -32.6 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 64; `ORC-N6O4SD4YLY` |  |
| β |  | -19.3 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 61; `ORC-DQVSTZFNNC` |  |
| β |  | -8.6 kJ/mol (basis unstated) |  | DFT |  |  | [2] Ukita 2007 | Table 1, p. 4, row 65; `ORC-SMZN2E6OVH` |  |
| γ-ZrH |  | -41.4 kJ/mol-atom | 0 | DFT |  |  | [3] Zhong 2012 | Table 3, p. 2, row 1; `ORC-2HIALGKH6B.170120` |  |
| γ-ZrH |  | -41.24 kJ/mol (basis unstated) |  | model |  |  | [2] Ukita 2007 | Table 2, p. 5, row 4; `ORC-WHKGRL6PHR.272f8a` |  |
| δ-ZrH2 | [ZrH2](https://data.orchid-project.org/compounds/ZrH2.html) | -56.83 kJ/mol-atom |  | model | -64.62 (mp-aaaabjyc) | -53.846 (oqmd-18857) | [3] Zhong 2012; _cites Dupin 1999_ [doi](https://doi.org/10.1016/s0022-3115%2899%2900125-7) | Table 3, p. 2, row 4; `ORC-BDQIZ33WUN.1f06ca` |  |
| δ-ZrH2 |  | -54.76 kJ/mol-atom | 0 | DFT |  |  | [3] Zhong 2012 | Table 3, p. 2, row 5; `ORC-36JRTTLT2M.c91987` |  |
| δ-ZrH2 |  | -54 kJ/mol (basis unstated) |  | model |  |  | [2] Ukita 2007 | Table 2, p. 5, row 5; `ORC-HHIENXB34Z.0c26a1` |  |
| ε-ZrH2 | [ZrH2](https://data.orchid-project.org/compounds/ZrH2.html) | -56.07 kJ/mol-atom |  | model | -64.62 (mp-aaaabjyc) | -53.846 (oqmd-18857) | [3] Zhong 2012; _cites Dupin 1999_ [doi](https://doi.org/10.1016/s0022-3115%2899%2900125-7) | Table 3, p. 2, row 2; `ORC-PY3JZ4K46I.4ace32` |  |
| ε-ZrH2 |  | -55.72 kJ/mol-atom | 0 | DFT |  |  | [3] Zhong 2012 | Table 3, p. 2, row 3; `ORC-7QYEKFSJNB.3dc60f` |  |
| ε-ZrH2 |  | -54.88 kJ/mol (basis unstated) |  | model |  |  | [2] Ukita 2007 | Table 2, p. 5, row 6; `ORC-MNJYYK3LRZ.47c537` |  |

## Other properties

### Activity / EMF / Gibbs energy (50)

Table: Activity / EMF / Gibbs energy, H–Zr system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Activity; _printed: aγ-ZrH_ | 1 1 | 400 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 1; `ORC-TVCTYGJPUQ.c23deb` |  |
| Activity; _printed: aδ-ZrH2-x_ | 0.11 1 | 400 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 1; `ORC-2UJBLA3NAW.1f0502` |  |
| Activity; _printed: a\_ε-ZrH2_ | 0.11 1 | 400 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 1; `ORC-D5XEQT7QVN.07a4ce` |  |
| Activity; _printed: aγ-ZrH_ | 1 1 | 450 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 2; `ORC-D34ZF6LOPD.f52ad4` |  |
| Activity; _printed: aδ-ZrH2-x_ | 0.15 1 | 450 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 2; `ORC-KBQQX5LWJD.e7a92c` |  |
| Activity; _printed: a\_ε-ZrH2_ | 0.15 1 | 450 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 2; `ORC-LTS2JX6JUR.9099de` |  |
| Activity; _printed: aγ-ZrH_ | 1 1 | 500 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 3; `ORC-NV7GON45NP.929720` |  |
| Activity; _printed: aδ-ZrH2-x_ | 0.18 1 | 500 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 3; `ORC-2252Y6GIIT.1c840a` |  |
| Activity; _printed: a\_ε-ZrH2_ | 0.18 1 | 500 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 3; `ORC-OHDNMDBVML.5eeb9d` |  |
| Activity; _printed: aγ-ZrH_ | 1 1 | 550 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 4; `ORC-GA7PT7JPI7.834491` |  |
| Activity; _printed: aδ-ZrH2-x_ | 0.21 1 | 550 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 4; `ORC-MRVOPPU3TD.d328c9` |  |
| Activity; _printed: a\_ε-ZrH2_ | 0.21 1 | 550 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 4; `ORC-OW7FLDM6AC.6486b5` |  |
| Activity; _printed: aγ-ZrH_ | 1 1 | 600 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 5; `ORC-QJHTDMSZ2J.57885d` |  |
| Activity; _printed: aδ-ZrH2-x_ | 0.24 1 | 600 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 5; `ORC-E2XYBOWGEP.615257` |  |
| Activity; _printed: a\_ε-ZrH2_ | 0.24 1 | 600 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 5; `ORC-SED6W2TMUT.3cca53` |  |
| Activity; _printed: aγ-ZrH_ | 1 1 | 650 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 6; `ORC-NNQDMHDCYE.df0f65` |  |
| Activity; _printed: aδ-ZrH2-x_ | 0.27 1 | 650 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 6; `ORC-76OCNZFEZ3.1b2224` |  |
| Activity; _printed: a\_ε-ZrH2_ | 0.27 1 | 650 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 6; `ORC-TIVSAYFZYD.cef19a` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 400 | UNKNOWN | model | [3] Zhong 2012 | Table 5, p. 3, row 1; `ORC-2UJBLA3NAW.72dc3a` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 400 | UNKNOWN | model | [3] Zhong 2012 | Table 6, p. 3, row 1; `ORC-TVCTYGJPUQ.37b63c` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 450 | UNKNOWN | model | [3] Zhong 2012 | Table 6, p. 3, row 2; `ORC-D34ZF6LOPD.fd0cf5` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 450 | UNKNOWN | model | [3] Zhong 2012 | Table 5, p. 3, row 2; `ORC-KBQQX5LWJD.42d385` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 500 | UNKNOWN | model | [3] Zhong 2012 | Table 5, p. 3, row 3; `ORC-2252Y6GIIT.34774c` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 500 | UNKNOWN | model | [3] Zhong 2012 | Table 6, p. 3, row 3; `ORC-NV7GON45NP.87b271` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 550 | UNKNOWN | model | [3] Zhong 2012 | Table 6, p. 3, row 4; `ORC-GA7PT7JPI7.d0fcf4` |  |
| Activity Zr; _printed: aZr_ | 1 1 | 550 | UNKNOWN | model | [3] Zhong 2012 | Table 5, p. 3, row 4; `ORC-MRVOPPU3TD.00eee2` |  |
| Activity Zr; _printed: a_Zr_ | 0.99 1 | 550 | UNKNOWN | model | [3] Zhong 2012 | Table 4, p. 3, row 4; `ORC-OW7FLDM6AC.5ee47d` |  |
| Activity Zr; _printed: aZr_ | 0.99 1 | 600 | UNKNOWN | model | [3] Zhong 2012 | Table 5, p. 3, row 5; `ORC-E2XYBOWGEP.3c9f8b` |  |
| Activity Zr; _printed: aZr_ | 0.99 1 | 600 | UNKNOWN | model | [3] Zhong 2012 | Table 6, p. 3, row 5; `ORC-QJHTDMSZ2J.048431` |  |
| Activity Zr; _printed: aZr_ | 0.99 1 | 650 | UNKNOWN | model | [3] Zhong 2012 | Table 5, p. 3, row 6; `ORC-76OCNZFEZ3.0b618b` |  |
| Activity Zr; _printed: aZr_ | 0.99 1 | 650 | UNKNOWN | model | [3] Zhong 2012 | Table 6, p. 3, row 6; `ORC-NNQDMHDCYE.b31acc` |  |
| Activity Zr; _printed: a_Zr_ | 0.98 1 | 650 | UNKNOWN | model | [3] Zhong 2012 | Table 4, p. 3, row 6; `ORC-TIVSAYFZYD.1bae4b` |  |
| Gibbs energy; _printed: G0(ZrH)_ | -70801.3 unknown | 400 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 1; `ORC-TVCTYGJPUQ.a95edf` |  |
| Gibbs energy; _printed: G0(δ-ZrH2-x)_ | -107087 unknown | 400 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 1; `ORC-2UJBLA3NAW.2bf97b` |  |
| Gibbs energy; _printed: G0(ε-ZrH2)_ | -130607 unknown | 400 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 1; `ORC-D5XEQT7QVN.c1f064` |  |
| Gibbs energy; _printed: G0(ZrH)_ | -73207 unknown | 450 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 2; `ORC-D34ZF6LOPD.0c0eea` |  |
| Gibbs energy; _printed: G0(δ-ZrH2-x)_ | -108737 unknown | 450 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 2; `ORC-KBQQX5LWJD.2679fa` |  |
| Gibbs energy; _printed: G0(ε-ZrH2)_ | -131665 unknown | 450 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 2; `ORC-LTS2JX6JUR.f9eb4b` |  |
| Gibbs energy; _printed: G0(ZrH)_ | -75848.6 unknown | 500 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 3; `ORC-NV7GON45NP.1bc595` |  |
| Gibbs energy; _printed: G0(δ-ZrH2-x)_ | -110617 unknown | 500 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 3; `ORC-2252Y6GIIT.aa1ec9` |  |
| Gibbs energy; _printed: G0(ε-ZrH2)_ | -132506 unknown | 500 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 3; `ORC-OHDNMDBVML.e19880` |  |
| Gibbs energy; _printed: G0(ZrH)_ | -78704.9 unknown | 550 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 4; `ORC-GA7PT7JPI7.0ce463` |  |
| Gibbs energy; _printed: G0(δ-ZrH2-x)_ | -112678 unknown | 550 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 4; `ORC-MRVOPPU3TD.52b709` |  |
| Gibbs energy; _printed: G0(ε-ZrH2)_ | -133049 unknown | 550 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 4; `ORC-OW7FLDM6AC.4b8fa6` |  |
| Gibbs energy; _printed: G0(ZrH)_ | -81758.7 unknown | 600 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 5; `ORC-QJHTDMSZ2J.c09e1b` |  |
| Gibbs energy; _printed: G0(δ-ZrH2-x)_ | -114873 unknown | 600 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 5; `ORC-E2XYBOWGEP.ebc8f0` |  |
| Gibbs energy; _printed: G0(ε-ZrH2)_ | -133218 unknown | 600 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 5; `ORC-SED6W2TMUT.70c759` |  |
| Gibbs energy; _printed: G0(ZrH)_ | -84995.6 unknown | 650 | γ-ZrH; _alloy: Zr 0.5_ | model | [3] Zhong 2012 | Table 6, p. 3, row 6; `ORC-NNQDMHDCYE.942752` |  |
| Gibbs energy; _printed: G0(δ-ZrH2-x)_ | -117152 unknown | 650 | δ-ZrH2-x | model | [3] Zhong 2012 | Table 5, p. 3, row 6; `ORC-76OCNZFEZ3.a9b332` |  |
| Gibbs energy; _printed: G0(ε-ZrH2)_ | -132953 unknown | 650 | ε-ZrH2; _alloy: Zr 0.333333_ | model | [3] Zhong 2012 | Table 4, p. 3, row 6; `ORC-TIVSAYFZYD.c6b373` |  |

### Crystal structure (46)

Table: Crystal structure, H–Zr system

| Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote |
|---|---:|---:|---|---|---|---|---|
| Lattice a; _printed: lattice parameter a_ | 11.726 Å |  | α; _alloy: H 0.2, Zr 0.8_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 54; `ORC-4AKXLMAAIH.3d67c0` |  |
| Lattice a; _printed: lattice parameter a_ | 11.115 Å |  | α; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 55; `ORC-56WZEKT5CG.b60e6d` |  |
| Lattice a; _printed: lattice parameter a_ | 3.341 Å |  | α; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 57; `ORC-RQZZDFZKSN.fbb8f5` |  |
| Lattice a; _printed: lattice parameter a_ | 4.138 Å |  | β; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 62; `ORC-BTMR3EK7XJ.6e8280` |  |
| Lattice a; _printed: lattice parameter a_ | 6.474 Å |  | β; _alloy: H 0.8, Zr 0.2_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 65; `ORC-RNEPWA4Y2L.c52807` |  |
| Lattice a; _printed: lattice parameter a_ | 5.317 Å |  | β; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 61; `ORC-XNV6C4G2FK.3a2fe0` |  |
| Lattice a; _printed: lattice parameter a_ | 4.586 Å |  | γ-ZrH; _alloy: Zr 0.5_ | model | [2] Ukita 2007 | Table 2, p. 5, row 4; `ORC-A3WPNYMCYT.024653` |  |
| Lattice a; _printed: a_ | 4.777 Å |  | δ-ZrH2; _alloy: Zr 0.333333_ | model | [2] Ukita 2007 | Table 2, p. 5, row 5; `ORC-YWI2EOJZMR.950640` |  |
| Lattice a; _printed: lattice parameter a_ | 3.536 Å |  | ε-ZrH2; _alloy: Zr 0.333333_ | model | [2] Ukita 2007 | Table 2, p. 5, row 6; `ORC-2DYUASSI7R.a073b5` |  |
| Lattice b; _printed: lattice parameter b_ | 3.242 Å |  | α; _alloy: H 0.2, Zr 0.8_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 54; `ORC-4AKXLMAAIH.9164a9` |  |
| Lattice b; _printed: lattice parameter b_ | 3.251 Å |  | α; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 55; `ORC-56WZEKT5CG.b6d6cd` |  |
| Lattice b; _printed: lattice parameter b_ | 5.35 Å |  | α; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 57; `ORC-RQZZDFZKSN.11b65b` |  |
| Lattice b; _printed: lattice parameter b_ | 4.947 Å |  | β; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 62; `ORC-BTMR3EK7XJ.0b3bd8` |  |
| Lattice b; _printed: lattice parameter b_ | 3.83 Å |  | β; _alloy: H 0.8, Zr 0.2_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 65; `ORC-RNEPWA4Y2L.e60b9a` |  |
| Lattice b; _printed: lattice parameter b_ | 3.539 Å |  | β; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 61; `ORC-XNV6C4G2FK.dec947` |  |
| Lattice b; _printed: b_ | 4.586 Å |  | γ-ZrH; _alloy: Zr 0.5_ | model | [2] Ukita 2007 | Table 2, p. 5, row 4; `ORC-A3WPNYMCYT.7a8eca` |  |
| Lattice b; _printed: b_ | 4.777 Å |  | δ-ZrH2; _alloy: Zr 0.333333_ | model | [2] Ukita 2007 | Table 2, p. 5, row 5; `ORC-YWI2EOJZMR.644557` |  |
| Lattice b; _printed: b_ | 3.536 Å |  | ε-ZrH2; _alloy: Zr 0.333333_ | model | [2] Ukita 2007 | Table 2, p. 5, row 6; `ORC-2DYUASSI7R.7e3448` |  |
| Lattice c; _printed: lattice parameter c_ | 5.585 Å |  | α; _alloy: H 0.2, Zr 0.8_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 54; `ORC-4AKXLMAAIH.9dd652` |  |
| Lattice c; _printed: lattice parameter c_ | 6.29 Å |  | α; _alloy: H 0.667, Zr 0.333_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 59; `ORC-4V25NFWK7T.e99312` |  |
| Lattice c; _printed: lattice parameter c_ | 5.453 Å |  | α; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 55; `ORC-56WZEKT5CG.a71f9c` |  |
| Lattice c; _printed: lattice parameter c_ | 5.49 Å |  | α; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 57; `ORC-RQZZDFZKSN.eeabdf` |  |
| Lattice c; _printed: lattice parameter c_ | 5.041 Å |  | β; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 62; `ORC-BTMR3EK7XJ.569902` |  |
| Lattice c; _printed: lattice parameter c_ | 4.337 Å |  | β; _alloy: H 0.667, Zr 0.333_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 63; `ORC-FU4MGICENJ.cca1ff` |  |
| Lattice c; _printed: lattice parameter c_ | 5.542 Å |  | β; _alloy: H 0.8, Zr 0.2_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 65; `ORC-RNEPWA4Y2L.93e82a` |  |
| Lattice c; _printed: lattice parameter c_ | 5.251 Å |  | β; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 61; `ORC-XNV6C4G2FK.728177` |  |
| Lattice c; _printed: lattice parameter c_ | 4.948 Å |  | γ-ZrH; _alloy: Zr 0.5_ | model | [2] Ukita 2007 | Table 2, p. 5, row 4; `ORC-A3WPNYMCYT.a7df52` |  |
| Lattice c; _printed: c_ | 4.777 Å |  | δ-ZrH2; _alloy: Zr 0.333333_ | model | [2] Ukita 2007 | Table 2, p. 5, row 5; `ORC-YWI2EOJZMR.c98fa2` |  |
| Lattice c; _printed: lattice parameter c_ | 4.44 Å |  | ε-ZrH2; _alloy: Zr 0.333333_ | model | [2] Ukita 2007 | Table 2, p. 5, row 6; `ORC-2DYUASSI7R.28d2ef` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | α; _alloy: H 0.2, Zr 0.8_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 54; `ORC-4AKXLMAAIH.6ae437` |  |
| lattice unspecified axis; _printed: β_ | 117.04 ° |  | α; _alloy: H 0.2, Zr 0.8_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 54; `ORC-4AKXLMAAIH.6c7a14` |  |
| lattice unspecified axis; _printed: β_ | 120 ° |  | α; _alloy: H 0.667, Zr 0.333_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 59; `ORC-4V25NFWK7T.14b1a3` |  |
| lattice unspecified axis; _printed: lattice parameter a=b_ | 3.264 Å |  | α; _alloy: H 0.667, Zr 0.333_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 59; `ORC-4V25NFWK7T.5913b9` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | α; _alloy: H 0.667, Zr 0.333_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 59; `ORC-4V25NFWK7T.bc45bc` |  |
| lattice unspecified axis; _printed: β_ | 103.09 ° |  | α; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 55; `ORC-56WZEKT5CG.249181` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | α; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 55; `ORC-56WZEKT5CG.c49ae1` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | α; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 57; `ORC-RQZZDFZKSN.fe530a` |  |
| lattice unspecified axis; _printed: lattice parameter a=b=c_ | 3.84 Å |  | β; _alloy: H 0.75, Zr 0.25_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 64; `ORC-5CUQEP6YZZ.60a2d6` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | β; _alloy: H 0.75, Zr 0.25_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 64; `ORC-5CUQEP6YZZ.e6efb7` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | β; _alloy: H 0.5, Zr 0.5_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 62; `ORC-BTMR3EK7XJ.3c3a74` |  |
| lattice unspecified axis; _printed: lattice parameter a=b_ | 3.554 Å |  | β; _alloy: H 0.667, Zr 0.333_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 63; `ORC-FU4MGICENJ.81cf91` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | β; _alloy: H 0.667, Zr 0.333_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 63; `ORC-FU4MGICENJ.c1f127` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | β; _alloy: H 0.8, Zr 0.2_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 65; `ORC-RNEPWA4Y2L.36f1eb` |  |
| lattice unspecified axis; _printed: β_ | 111.23 ° |  | β; _alloy: H 0.8, Zr 0.2_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 65; `ORC-RNEPWA4Y2L.89142c` |  |
| lattice unspecified axis; _printed: α_ | 90 ° |  | β; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 61; `ORC-XNV6C4G2FK.46e91a` |  |
| lattice unspecified axis; _printed: β_ | 87.96 ° |  | β; _alloy: H 0.333, Zr 0.667_ | DFT | [2] Ukita 2007 | Table 1, p. 4, row 61; `ORC-XNV6C4G2FK.beff9a` |  |

## Sources

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

1. E. Königsberger, G. Eriksson, W.A. Oates, Optimisation of the thermodynamic properties of the Ti–H and Zr–H systems, Journal of Alloys and Compounds 299, 148-152 (2000). [doi:10.1016/s0925-8388(99)00816-6](https://doi.org/10.1016/s0925-8388%2899%2900816-6)
2. Shusuke Ukita, Hiroshi Ohtani, Mitsuhiro Hasebe, Thermodynamic Analysis of the Ti-H and Zr-H Binary Phase Diagrams, J. Japan Inst. Metals 71, 721-729 (2007). [doi:10.2320/jinstmet.71.721](https://doi.org/10.2320/jinstmet.71.721)
3. Yu Zhong, Digby D. Macdonald, Thermodynamics of the Zr–H binary system related to nuclear fuel sheathing and pressure tube hydriding, Journal of Nuclear Materials 423, 87-92 (2012). [doi:10.1016/j.jnucmat.2012.01.016](https://doi.org/10.1016/j.jnucmat.2012.01.016)

## 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-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); 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); 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.

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_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/).