Si2Sr: enthalpy of formation

16 accepted literature formation-enthalpy value(s) (experimental 4, model 1, DFT 10, unspecified 1); experimental median -41.5 kJ/mol-atom (n = 4); Materials Project -30.715 kJ/mol-atom (mp-aaaaacol); OQMD -35.357 kJ/mol-atom (oqmd-6867).

Systems: Si–Sr

Literature values

Enthalpy of formation of Si2Sr reported in the literature (16)
Value	Phase as printed	T (K)	Class	Method	System	Source	Location
-42.7 kJ/mol-atom	α-SrSi2	298.15	experimental		Si–Sr	[1] Garay 2009 cites Balducci 2006 doi	Table 2, p. 4, row 22 report
-42.7 kJ/mol-atom ± 4.3	α-Si2Sr	298.15	experimental		Si–Sr	[2] Li 2011 cites Balducci 2006 doi	Table 2, p. 2, row 13 report
-40.3 kJ/mol-atom ± 3.7	β-Si2Sr	298.15	experimental		Si–Sr	[2] Li 2011 cites Balducci 2006 doi	Table 2, p. 2, row 10 report
-40.3 kJ/mol-atom	β-SrSi2	298.15	experimental		Si–Sr	[1] Garay 2009 cites Balducci 2006 doi	Table 2, p. 4, row 26 report
-67.3 kJ/mol-atom	α-SrSi2	298.15	model		Si–Sr	[1] Garay 2009 cites Gordienko 1997 doi	Table 2, p. 4, row 17 report
-44.7 kJ/mol-atom	β-SrSi2	298.15	DFT	first-principles LDA	Si–Sr	[1] Garay 2009	Table 2, p. 4, row 23 report
-44.7 kJ/mol-atom	β-Si2Sr	298.15	DFT	first-principles LDA	Si–Sr	[2] Li 2011 cites Garay 2009 doi	Table 2, p. 2, row 12 report
-42 kJ/mol-atom	α-Si2Sr		DFT	first-principles LDA	Si–Sr	[2] Li 2011 cites Garay 2009 doi	Table 2, p. 2, row 15 report
-42 kJ/mol-atom	α-SrSi2	298.15	DFT	first-principles LDA	Si–Sr	[1] Garay 2009	Table 2, p. 4, row 19 report
-35.9 kJ/mol-atom	β-SrSi2	298.15	DFT	first-principles GGA	Si–Sr	[1] Garay 2009	Table 2, p. 4, row 24 report
-35.9 kJ/mol-atom	β-Si2Sr	298.15	DFT	first-principles GGA	Si–Sr	[2] Li 2011 cites Garay 2009 doi	Table 2, p. 2, row 11 report
-35.8 kJ/mol-atom	α-SrSi2	298.15	DFT	first-principles GGA	Si–Sr	[1] Garay 2009 cites Brutti 2008 doi	Table 2, p. 4, row 21 report
-35.7 kJ/mol-atom	β-SrSi2	298.15	DFT	first-principles GGA	Si–Sr	[1] Garay 2009 cites Brutti 2008 doi	Table 2, p. 4, row 25 report
-35.7 kJ/mol-atom	α-Si2Sr		DFT	first-principles GGA	Si–Sr	[2] Li 2011 cites Garay 2009 doi	Table 2, p. 2, row 14 report
-35.7 kJ/mol-atom	α-SrSi2	298.15	DFT	first-principles GGA	Si–Sr	[1] Garay 2009	Table 2, p. 4, row 20 report
-34.6 kJ/mol-atom	α-SrSi2	298.15	unspecified		Si–Sr	[1] Garay 2009 cites Imai 2002 doi	Table 2, p. 4, row 18 report

Uncertainty budget

Components kept separate, in the value's unit (literature SCHEMA.md, UNCERTAINTY_CALIBRATION.md): effective = max(sqrt(max(printed, reading, method)^2 + composition^2 + conversion^2), scatter). The method floor is the robust between-study scatter of the method class in ORCHID (calibrated) or a documented prior; printed values and printed uncertainties are unchanged.

Uncertainty budget of the literature values of Si2Sr
Value	Unit	Printed	Reading	Method (class, basis)	Effective
-42.7	kJ/mol-atom		0.05	3.5 (unknown, calibrated)	3.5
-42.7	kJ/mol-atom	4.3	0.05	3.5 (unknown, calibrated)	4.3
-40.3	kJ/mol-atom	3.7	0.05	3.5 (unknown, calibrated)	3.7
-40.3	kJ/mol-atom		0.05	3.5 (unknown, calibrated)	3.5
-67.3	kJ/mol-atom		0.05	3.9 (model_calculated, calibrated)	3.9
-44.7	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-44.7	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-42	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-42	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-35.9	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-35.9	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-35.8	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-35.7	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-35.7	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-35.7	kJ/mol-atom		0.05	9.966 (dft, calibrated)	9.966
-34.6	kJ/mol-atom		0.05	3.5 (unknown, calibrated)	3.5

DFT formation energies

Lowest-energy entries at this composition. Materials Project and OQMD use different energy references and are never averaged. 1 eV/atom = 96.485 kJ/mol-atom.

DFT formation energy of Si2Sr
Source	Entry	kJ/mol-atom	eV/atom	Space group	E above hull (kJ/mol-atom)	E above hull (eV/atom)	Theoretical
Materials Project	mp-aaaaacol	-30.715	-0.318344	I4_1/amd	0	0	no
OQMD	oqmd-6867	-35.357	-0.366453	I41/amd	0	0	no

DFT sources: A. Jain et al., Commentary: The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002. doi:10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501-1509; S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010. doi:10.1007/s11837-013-0755-4 (CC BY 4.0);

Sources

Andres Garay, Gerardo Trápaga, Zi-Kui Liu, Raymundo Arróyave, Thermodynamic modeling of the Si–Sr system, Calphad 33, 550-556 (2009). doi:10.1016/j.calphad.2009.07.001
Kai Li, Shuhong Liu, Chunsheng Sha, Yong Du, A thermodynamic reassessment of the Si–Sr system, Calphad 35, 594-600 (2011). doi:10.1016/j.calphad.2011.09.007

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-Parity: DFT-vs-experiment formation-enthalpy benchmark (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735943
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); 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); G. Kim, S. V. Meschel, P. Nash, W. Chen, Experimental formation enthalpies for intermetallic phases and other inorganic compounds, Scientific Data 4 (2017) 170162, https://doi.org/10.1038/sdata.2017.162; 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.

@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_dft_benchmark_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Parity: DFT-vs-experiment formation-enthalpy benchmark}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735943},
  url       = {https://doi.org/10.5281/zenodo.23735943},
  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}
}