Ca–H system

23 accepted literature values from 1 paper(s) (experimental 12, DFT 11); 2 calculated phase diagram(s). 8 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: JSON · CSV · interactive explorer · interactive phase diagram · phases (7) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	12
DFT	11

Accepted values by property group
Property group	Values
formation	10
crystal structure	13

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.

Assessments with a calculated phase diagram
TDB file	Assessment	SHA-256	Links
CaH-11Wan.tdb	K. Wang, J. Du, X. Kong, X. Zeng, J. Zou, Z. Li, Z. Wu, Int. J. Hydrogen Energy, 36, 13632-39(2011). doi:10.1016/j.ijhydene.2011.08.018	`10f2af8543f879eea519b3257ccb4ed867e5a1c0b5eb1e7f2644b333ddf32816`	viewer · TDB · JSON
CaH-12Wan.tdb	M. Wang, W. Sun, C. Sha, B. Hu, Y. Du, L. Sun, H. Xu, J. Wang, S. Liu, J. Phase Equilib. Diffus., 33, 89-96(2012). doi:10.1007/s11669-012-9997-z	`e8d5c286231e6b11e61859273f6b9ed396323a357b3c9b11e6104e8c44e9ad60`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
CaH-11Wan.tdb	1257.01	LIQUID (x(H) 0.44007) + CAH2_BETA (x(H) 0.66667) + GAS (x(H) 0.99826)
CaH-11Wan.tdb	1160.05	LIQUID (x(H) 0.29113) + BCC_A2 (x(H) 0.32471) + CAH2_BETA (x(H) 0.66667)
CaH-11Wan.tdb	1053.15	CAH2_C37 (x(H) 0.66667) + CAH2_BETA (x(H) 0.66667) + GAS (x(H) 1)
CaH-11Wan.tdb	1053.15	CAH2_BETA (x(H) 0.66667) + CAH2_C37 (x(H) 0.66667) + GAS (x(H) 1)
CaH-11Wan.tdb	1053.15	BCC_A2 (x(H) 0.26515) + CAH2_C37 (x(H) 0.66667) + CAH2_BETA (x(H) 0.66667)
CaH-11Wan.tdb	878.76	BCC_A2 (x(H) 0.12172) + HCP_A3 (x(H) 0.16929) + CAH2_C37 (x(H) 0.66667)
CaH-11Wan.tdb	688.01	FCC_A1 (x(H) 0.0061) + BCC_A2 (x(H) 0.01242) + HCP_A3 (x(H) 0.01954)
CaH-11Wan.tdb	624.48	FCC_A1 (x(H) 0.00498) + HCP_A3 (x(H) 0.03266) + CAH2_C37 (x(H) 0.66667)
CaH-12Wan.tdb	1255.76	LIQUID (x(H) 0.43171) + CAH2_BETA (x(H) 0.66667) + GAS (x(H) 0.99851)
CaH-12Wan.tdb	1163.62	LIQUID (x(H) 0.29214) + BCC_A2 (x(H) 0.3427) + CAH2_BETA (x(H) 0.66667)
CaH-12Wan.tdb	1053.28	CAH2_C37 (x(H) 0.66667) + CAH2_BETA (x(H) 0.66667) + GAS (x(H) 1)
CaH-12Wan.tdb	1053.28	BCC_A2 (x(H) 0.25743) + CAH2_C37 (x(H) 0.66667) + CAH2_BETA (x(H) 0.66667)
CaH-12Wan.tdb	872.02	BCC_A2 (x(H) 0.11667) + HCP_A3 (x(H) 0.14594) + CAH2_C37 (x(H) 0.66667)
CaH-12Wan.tdb	720.47	BCC_A2 (x(H) 0.00853) + FCC_A1 (x(H) 0.00947) + HCP_A3 (x(H) 0.01318)
CaH-12Wan.tdb	630.31	FCC_A1 (x(H) 0.01797) + HCP_A3 (x(H) 0.03502) + CAH2_C37 (x(H) 0.66667)

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull CaH-11Wan

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.

Enthalpies of formation, Ca–H system (10)
Phase	Value	T (K)	Class	Source	Location
CaH2	-208 kJ/mol (basis unstated)	1093	experimental	[1] Wang 2011 cites Johnson 1939 doi	Table 1, p. 3, row 3 report
CaH2	-188 kJ/mol (basis unstated)	1093	experimental	[1] Wang 2011 cites Treadwell 1953	Table 1, p. 3, row 2 report
CaH2	-184 kJ/mol (basis unstated)	298.15	experimental	[1] Wang 2011 cites Mueller 1968	Table 1, p. 3, row 5 report
CaH2	-183.6 kJ/mol (basis unstated)	298.15	experimental	[1] Wang 2011 cites Lide 2002	Table 1, p. 3, row 6 report
CaH2	-172.1 kJ/mol (basis unstated)	0	DFT	[1] Wang 2011 cites Wolverton 2007 doi	Table 1, p. 3, row 4 report
CaH2	-172 kJ/mol (basis unstated)	0	DFT	[1] Wang 2011 cites Wolverton 2004 doi	Table 1, p. 3, row 7 report
CaH2	-170.2 kJ/mol (basis unstated)	298.15	experimental	[1] Wang 2011 cites Mueller 1968	Table 1, p. 3, row 5 report
CaH2	-167.3 kJ/mol (basis unstated)	0	DFT	[1] Wang 2011	Table 1, p. 3, row 1 report
CaH2	-162.9 kJ/mol (basis unstated)	0	DFT	[1] Wang 2011	Table 1, p. 3, row 1 report
CaH2	-161.1 kJ/mol (basis unstated)	0	DFT	[1] Wang 2011 cites Wolverton 2007 doi	Table 1, p. 3, row 4 report

Other properties

Crystal structure (13)

Crystal structure, Ca–H system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Lattice a	5.157 Å	0	CaH alloy: H 0.5	DFT	[1] Wang 2011	Table 3, p. 5, row 6 report
Lattice a	4.366 Å	0	CaH1.5 alloy: H 0.6	DFT	[1] Wang 2011	Table 3, p. 5, row 7 report
Lattice a	5.92 Å		αCaH2 alloy: H 0.666667	experimental	[1] Wang 2011	Table 3, p. 5, row 8 report
Lattice a	5.92 Å	0	αCaH2 alloy: H 0.666667	DFT	[1] Wang 2011	Table 3, p. 5, row 1 report
Lattice a	5.445 Å		βCaH2 alloy: H 0.666667	experimental	[1] Wang 2011	Table 3, p. 5, row 10 report
Lattice a	5.445 Å	0	βCaH2 alloy: H 0.666667	DFT	[1] Wang 2011	Table 3, p. 5, row 3 report
Lattice a	5.948 Å	298.15	αCaH2 alloy: H 0.666667	experimental	[1] Wang 2011	Table 3, p. 5, row 2 report
Lattice b	3.582 Å		αCaH2 alloy: H 0.666667	experimental	[1] Wang 2011	Table 3, p. 5, row 8 report
Lattice b	3.582 Å	0	αCaH2 alloy: H 0.666667	DFT	[1] Wang 2011	Table 3, p. 5, row 1 report
Lattice b	3.607 Å	298.15	αCaH2 alloy: H 0.666667	experimental	[1] Wang 2011	Table 3, p. 5, row 2 report
Lattice c	6.788 Å		αCaH2 alloy: H 0.666667	experimental	[1] Wang 2011	Table 3, p. 5, row 8 report
Lattice c	6.788 Å	0	αCaH2 alloy: H 0.666667	DFT	[1] Wang 2011	Table 3, p. 5, row 1 report
Lattice c	6.852 Å	298.15	αCaH2 alloy: H 0.666667	experimental	[1] Wang 2011	Table 3, p. 5, row 2 report

Sources

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

Kun Wang, Junlin Du, Xiangcheng Kong, Xiaoqin Zeng, Jianxin Zou, Zhilin Li et al., Ab initio and thermodynamic investigation on the Ca–H system, International Journal of Hydrogen Energy 36, 13632-13639 (2011). doi:10.1016/j.ijhydene.2011.08.018

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). doi:10.5281/zenodo.23735569
R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). doi: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). doi: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). doi: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.

@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}
}