Ca system

68 accepted literature values from 13 paper(s) (experimental 11, model 5, DFT 39, unspecified 13); 0 calculated phase diagram(s).

Data: JSON · CSV · interactive explorer · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	11
model	5
DFT	39
unspecified	13

Accepted values by property group
Property group	Values
invariant reaction	2
phase transition	12
formation	5
heat capacity / entropy / enthalpy	4
crystal structure	45

Invariant reactions (literature)

Invariant reactions reported in the literature for the Ca system (2)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location	Quote
716.15	polymorphic: βCa ↔ αCa	αCa:	experimental	[1] Cartigny 2004 cites Chase 1985	Table 3, p. 4, row 3 report
716.03	polymorphic: βCa ↔ αCa	αCa:	model	[1] Cartigny 2004	Table 3, p. 4, row 2 report

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 system (5)
Phase	Value	Class	Source	Location
C15-Ca2Ca	8.182 kJ/mol-atom	DFT	[2] Ozturk 2005	Table IV, p. 5, row 33 report
C15-Ca2Ca	8.201 kJ/mol-atom	DFT	[2] Ozturk 2005	Table IV, p. 5, row 31 report
C15-Ca2Ca	8.201 kJ/mol-atom	DFT	[2] Ozturk 2005	Table IV, p. 5, row 34 report
C15-Ca2Ca	8.708 kJ/mol-atom	DFT	[2] Ozturk 2005	Table IV, p. 5, row 32 report
fcc-Ca	0 kJ/mol-atom	unspecified	[3] Zhong 2006	Table 2, p. 4, row 22 report

Other properties

Phase transition (12)

Phase transition, Ca system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	714.28 K	714.28	polymorphic: Ca-fcc -> Ca-bcc Ca-fcc: Ca 1	unspecified	[4] ISLAM 2005 cites ref. 28	Table IV, p. 8, row 8 report
Phase transition	715.9 K	715.9	polymorphic: Ca-fcc -> Ca-bcc Ca-fcc: Ca 1	model	[4] ISLAM 2005	Table IV, p. 8, row 9 report
Phase transition	715.9 K	715.9	polymorphic: Ca-fcc -> Ca-bcc Ca-fcc: Ca 1	unspecified	[4] ISLAM 2005 cites ref. 26	Table IV, p. 8, row 7 report
Phase transition	716 K	716	polymorphic: (βCa) -> (αCa) (βCa): Ca 1	model	[5] Huang 2008	Table 3, p. 3, row 19 report
Phase transition	716 K	716	polymorphic: (βCa) -> (αCa) (βCa): Ca 1	unspecified	[5] Huang 2008 cites Baren 1988 doi	Table 3, p. 3, row 20 report
Phase transition	716 K	716	polymorphic: Ca-fcc -> Ca-bcc Ca-fcc:	model	[4] ISLAM 2005	Table II, p. 5, row 13 report
Phase transition	716 K	716	polymorphic: Ca-fcc -> Ca-bcc Ca-fcc:	unspecified	[4] ISLAM 2005 cites ref. 15	Table II, p. 5, row 12 report
Phase transition	716 K	716	polymorphic: Ca-fcc -> Ca-bcc Ca-fcc:	unspecified	[4] ISLAM 2005 cites ref. 14	Table II, p. 5, row 11 report
Phase transition	728 K	728	Ca	experimental	[6] Risold 1996	p. 2 report	Bruzzone reports that the ,0Ca to &a transition in equilibrium with CasCu occurs at 728 K, which is 12 K higher than the value for pure Ca used in this work [SlDin].
Phase transition	1114.9 K	1114.9	congruent melting: L -> Ca-bcc L: Ca 1	unspecified	[4] ISLAM 2005 cites ref. 26	Table IV, p. 8, row 4 report
Phase transition	1115 K	1115	congruent melting: L -> Ca-bcc L: Ca 1	model	[4] ISLAM 2005	Table IV, p. 8, row 6 report
Phase transition	1116.66 K	1116.66	congruent melting: L -> Ca-bcc L: Ca 1	unspecified	[4] ISLAM 2005 cites ref. 28	Table IV, p. 8, row 5 report

Heat capacity / entropy / enthalpy (4)

Heat capacity / entropy / enthalpy, Ca system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy printed: S,298	43.38 J/mol (basis unstated)/K	0	α-Ca	DFT	[7] OHNO 2006	Table 2, p. 4, row 1 report
Entropy printed: S,298	41.42 J/mol (basis unstated)/K	298.15	α-Ca	experimental	[7] OHNO 2006 cites Dederichs 1981	Table 2, p. 4, row 2 report
Heat capacity printed: CP298	25.98 J/mol (basis unstated)/K	0	α-Ca	DFT	[7] OHNO 2006	Table 2, p. 4, row 1 report
Heat capacity printed: CP298	25.31 J/mol (basis unstated)/K	298.15	α-Ca	experimental	[7] OHNO 2006 cites Dederichs 1981	Table 2, p. 4, row 2 report

Crystal structure (45)

Crystal structure, Ca system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Lattice a	5.57 Å	0	(αCa) alloy: Ca 1	DFT	[8] Li 2013	Table 1, p. 2, row 5 report
Lattice a	4.453 Å	0	(βCa) alloy: Ca 1	DFT	[8] Li 2013	Table 1, p. 2, row 7 report
Lattice a	10.208 Å	0	C15-Ca2Ca alloy: Ca 1	DFT	[2] Ozturk 2005	Table III, p. 4, row 16 report
Lattice a	9.858 Å	0	C15-Ca2Ca alloy: Ca 1	DFT	[2] Ozturk 2005	Table III, p. 4, row 17 report
Lattice a	10.123 Å	0	C15-Ca2Ca alloy: Ca 1	DFT	[2] Ozturk 2005	Table III, p. 4, row 18 report
Lattice a	5.545 Å	0	Ca fcc	DFT	[9] Wang 2011	Table 3, p. 5, row 4 report
Lattice a	4.349 Å	0	bcc (A2) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 24 report
Lattice a	4.218 Å	0	bcc (A2) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 23 report
Lattice a	4.211 Å	0	bcc (A2) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 22 report
Lattice a	5.492 Å	0	fcc (A1) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 20 report
Lattice a	5.545 Å	0	fcc (A1) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 18 report
Lattice a	5.344 Å	0	fcc (A1) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 19 report
Lattice a	5.331 Å	0	fcc (A1) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 17 report
Lattice a	5.5884 Å		fcc (A1) alloy: Ca 1	experimental	[2] Ozturk 2005 cites Bernstein 1959 doi	Table I, p. 3, row 21 report
Lattice a printed: a	5.486 Å	0	fcc-Ca	unspecified	[3] Zhong 2006	Table 2, p. 4, row 22 report
Lattice a	3.769 Å	0	hcp (A3) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 26 report
Lattice a	3.775 Å	0	hcp (A3) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 25 report
Lattice a	3.864 Å	0	hcp (A3) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 27 report
Lattice a	4.345 Å	2	bcc (A2) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 18 report
Lattice a	4.48 Å	2	bcc (A2) alloy: Ca 1	experimental	[10] Zhong 2006 cites King 1982 doi	Table 1, p. 4, row 5 report
Lattice a	4.218 Å	2	bcc (A2) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 17 report
Lattice a	4.211 Å	2	bcc (A2) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 4 report
Lattice a	5.588 Å	2	fcc (A1) alloy: Ca 1	experimental	[10] Zhong 2006 cites King 1981 doi	Table 1, p. 4, row 3 report
Lattice a	5.344 Å	2	fcc (A1) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 14 report
Lattice a	5.486 Å	2	fcc (A1) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 15 report
Lattice a	5.331 Å	2	fcc (A1) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 1 report
Lattice a	5.545 Å	2	fcc (A1) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 2 report
Lattice a	3.862 Å	2	hcp (A3) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 21 report
Lattice a	3.775 Å	2	hcp (A3) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 6 report
Lattice a	3.764 Å	2	hcp (A3) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 20 report
Lattice a	5.5884 Å	221.5	fcc (αCa) fcc (αCa):	unspecified	[11] Smith 1988 cites ref. 2	Table I, p. 2, row 1 report
Lattice a	5.582 Å	298.15	(αCa) alloy: Ca 1	experimental	[8] Li 2013 cites Bruzzone 1966	Table 1, p. 2, row 4 report
Lattice a	0.55884 not_printed	298.15	(αCa) (αCa): Ca 1	unspecified	[12] Alcock 1986	Table 1, p. 2, row 1 report
Lattice a	4.48 Å	298.15	(βCa) alloy: Ca 1	experimental	[8] Li 2013 cites Bernstein 1959 doi	Table 1, p. 2, row 6 report
Lattice a	5.57 Å	298.15	Ca fcc	experimental	[9] Wang 2011	Table 3, p. 5, row 5 report
Lattice a	4.48 Å	642.5	bcc (βCa) bcc (βCa):	unspecified	[11] Smith 1988 cites ref. 2	Table I, p. 2, row 2 report
Lattice a	0.448 not_printed	1010.15	(βCa, Ba) (βCa, Ba): Ca 1	unspecified	[12] Alcock 1986 cites ref. 2	Table 1, p. 2, row 3 report
Lattice c	6.244 Å	0	hcp (A3) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 26 report
Lattice c	6.228 Å	0	hcp (A3) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 25 report
Lattice c	6.414 Å	0	hcp (A3) alloy: Ca 1	DFT	[2] Ozturk 2005	Table I, p. 3, row 27 report
Lattice c	6.411 Å	2	hcp (A3) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 21 report
Lattice c	6.228 Å	2	hcp (A3) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 6 report
Lattice c	6.263 Å	2	hcp (A3) alloy: Ca 1	DFT	[10] Zhong 2006	Table 1, p. 4, row 20 report
lattice unspecified axis printed: Lattice parameter	4.5 Å		Ca	experimental	[13] Zhang 2008 cites Lide 2002	Table 1, p. 2, row 2 report
lattice unspecified axis printed: Lattice parameter	4.4 Å	0	Ca	DFT	[13] Zhang 2008	Table 1, p. 2, row 1 report

Sources

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

Y. Cartigny, J.M. Fiorani, A. Maı̂tre, M. Vilasi, Thermodynamic assessment of the Ca–Pb system, Thermochimica Acta 414, 197-202 (2004). doi:10.1016/j.tca.2004.01.001
Koray Ozturk, Yu Zhong, Long-Qing Chen, Zi-Kui Liu, Jorge O. Sofo, C. Wolverton, Linking first-principles energetics to CALPHAD: An application to thermodynamic modeling of the Al-Ca binary system, Metall Mater Trans A 36, 5-13 (2005). doi:10.1007/s11661-005-0133-0
Yu Zhong, Jorge O. Sofo, Alan A. Luo, Zi-Kui Liu, Thermodynamics modeling of the Mg–Sr and Ca–Mg–Sr systems, Journal of Alloys and Compounds 421, 172-178 (2006). doi:10.1016/j.jallcom.2005.09.076
F. ISLAM, M. MEDRAJ, THERMODYNAMIC MODELLING OF THE Mg-Al-Ca SYSTEM, Canadian Metallurgical Quarterly 44, 523-536 (2005). doi:10.1179/cmq.2005.44.4.523
G.X. Huang, L.B. Liu, B.R. Jia, L.G. Zhang, Z.P. Jin, Thermodynamic modeling of the Ca–Ag binary system, Journal of Alloys and Compounds 460, 375-378 (2008). doi:10.1016/j.jallcom.2007.06.064
Daniel Risold, Bengt Hallstedt, Ludwig J. Gauckler, Hans Leo Lukas, Suzana G. Fries, Thermodynamic optimization of the Ca-Cu and Sr-Cu systems, Calphad 20, 151-160 (1996). doi:10.1016/s0364-5916(96)00022-3
M OHNO, A KOZLOV, R ARROYAVE, Z LIU, R SCHMIDFETZER, Thermodynamic modeling of the Ca–Sn system based on finite temperature quantities from first-principles and experiment, Acta Materialia 54, 4939-4951 (2006). doi:10.1016/j.actamat.2006.06.017
Xi Li, Kaiming Cheng, Xiaoming Yuan, Dongdong Zhao, Jinghua Xin, Weiwei Wang et al., Thermodynamic assessment of the Ga–X (X=B, Ca, Sr, Ba) systems supported by first-principles calculations, Calphad 43, 52-60 (2013). doi:10.1016/j.calphad.2013.09.002
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
Yu Zhong, Koray Ozturk, Jorge O. Sofo, Zi-Kui Liu, Contribution of first-principles energetics to the Ca–Mg thermodynamic modeling, Journal of Alloys and Compounds 420, 98-106 (2006). doi:10.1016/j.jallcom.2005.10.033
J. F. Smith, K. J. Lee, The Ca−V (Calcium-Vanadium), Sr−V (strontium-Vandadium), and Ba−V (Barium-Vanadium) systems, Bulletin of Alloy Phase Diagrams 9, 466-469 (1988). doi:10.1007/bf02881868
C. B. Alcock, V. P. Itkin, The Ba−Ca (Barium-Calcium) system, Bulletin of Alloy Phase Diagrams 7, 338-340 (1986). doi:10.1007/bf02873004
Hui Zhang, Yi Wang, Shunli Shang, Long-Qing Chen, Zi-Kui Liu, Thermodynamic modeling of Mg–Ca–Ce system by combining first-principles and CALPHAD method, Journal of Alloys and Compounds 463, 294-301 (2008). doi:10.1016/j.jallcom.2007.09.020

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 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_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}
}