Ag–O system

58 accepted literature values from 1 paper(s) (experimental 35, model 23); 1 calculated phase diagram(s). 9 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 (8) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	35
model	23

Accepted values by property group
Property group	Values
invariant reaction	16
phase transition	2
formation	9
heat capacity / entropy / enthalpy	7
activity / EMF / Gibbs energy	5
model expression	19

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
AgO-97Ass-LB.tdb	J. Assal, B. Hallstedt and L.J. Gauckler, J. Am. Ceram. Soc., 80, 3054-60(1997) doi:10.1111/j.1151-2916.1997.tb03232.x	`9f608fb28b4b4e31cd84c13d6756c0fd284a4dd09fe677a8805bdc771e6bc22d`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
AgO-97Ass-LB.tdb	1211.42	FCC_A1 (x(O) 5.700e-4) + ION (x(O) 0.02078) + GAS (x(O) 1)

Convex hulls: Materials Project DFT hull · OQMD DFT hull

Invariant reactions (literature)

Invariant reactions reported in the literature for the Ag–O system (16)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
1228	L + O2 -> Ag (in O2)	L: O 0.0204	experimental	[1] Assal 1997 cites Sieverts 1909	Table III, p. 3, row 11 report
1226	L + O2 -> Ag (in air)	L: O 0.0097	model	[1] Assal 1997 cites Karakaya 1992 doi	Table III, p. 3, row 9 report
1224.2	L + O2 -> Ag (in air)	L: O 0.00981	model	[1] Assal 1997	Table III, p. 3, row 10 report
1224	L + O2 -> Ag (in air)		experimental	[1] Assal 1997 cites Allen 1932	Table III, p. 3, row 5 report
1223	L + O2 -> Ag (in air)	L: O 0.0087	experimental	[1] Assal 1997 cites Knacke 1968 doi	Table III, p. 3, row 8 report
1223	L + O2 -> Ag (in air)		experimental	[1] Assal 1997 cites Baker 1965 doi	Table III, p. 3, row 6 report
1219	L + O2 -> Ag (in air)	L: O 0.0099	experimental	[1] Assal 1997 cites Besson 1966	Table III, p. 3, row 7 report
1212	L + O2 -> Ag (in O2)	L: O 0.0209	model	[1] Assal 1997 cites Karakaya 1992 doi	Table III, p. 3, row 16 report
1212	L + O2 -> Ag (in O2)	L: O 0.0195	experimental	[1] Assal 1997 cites Knacke 1968 doi	Table III, p. 3, row 15 report
1212	L + O2 -> Ag (in O2)	L: O 0.021	experimental	[1] Assal 1997 cites Shah 1967	Table III, p. 3, row 14 report
1211.8	L + O2 -> Ag (in O2)	L: O 0.02053	model	[1] Assal 1997	Table III, p. 3, row 17 report
1211	L + O2 -> Ag (in O2)		experimental	[1] Assal 1997 cites Allen 1932	Table III, p. 3, row 12 report
1210	L + O2 -> Ag (in O2)		experimental	[1] Assal 1997 cites Baker 1965 doi	Table III, p. 3, row 13 report
803.5	eutectic: L -> Ag + Ag2O (eutectic)	L: O 0.2514	model	[1] Assal 1997	Table III, p. 3, row 3 report
803	eutectic: L -> Ag + Ag2O (eutectic)	L: O 0.22	experimental	[1] Assal 1997 cites Baker 1968	Table III, p. 3, row 2 report
780	eutectic: L -> Ag + Ag2O (eutectic)		experimental	[1] Assal 1997 cites Allen 1932	Table III, p. 3, row 1 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, Ag–O system (9)
Phase	Value	T (K)	Class	Source	Location
Ag2O	-31.1 kJ/mol (basis unstated)	298.15	model	[1] Assal 1997 cites Kubaschewski 1993	Table V, p. 6, row 4 report
Ag2O	-30.68 kJ/mol (basis unstated)	298.15	model	[1] Assal 1997	Table V, p. 6, row 6 report
Ag2O	-30.54 kJ/mol (basis unstated)	298.15	experimental	[1] Assal 1997 cites Pitzer 1937	Table V, p. 6, row 3 report
Ag2O	-29.99 kJ/mol (basis unstated)	773	model	[1] Assal 1997	Table V, p. 6, row 7 report
Ag2O	-29.44 kJ/mol (basis unstated)	609.5	model	[1] Assal 1997 cites Pitzer 1937	Table V, p. 6, row 5 report
Ag2O	-26.53 kJ/mol (basis unstated)	298.15	experimental	[1] Assal 1997 cites Lewis 1906	Table V, p. 6, row 1 report
Ag2O	-25.81 kJ/mol (basis unstated)	773	model	[1] Assal 1997	Table V, p. 6, row 7 report
Ag2O	-25.81 kJ/mol (basis unstated)	773	model	[1] Assal 1997	Table V, p. 6, row 8 report
Ag2O	-22.6 kJ/mol (basis unstated)	298.15	experimental	[1] Assal 1997 cites Mixter 1911	Table V, p. 6, row 2 report

Other properties

Phase transition (2)

Phase transition, Ag–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	1060 K	1060	Ag2O	model	[1] Assal 1997	p. 6 report	Below the calculated melting temperature of Ag2O (Tm 4 1060 K), stoichiometric Ag2O is described by SER °GAg2O - 2HSER = A + BT + CT ln T + DT 2 + FT -1 Ag - HO
Phase transition	1060.2 K	1060.2	L -> Ag2O L: O 0.3333	model	[1] Assal 1997	Table III, p. 3, row 4 report

Heat capacity / entropy / enthalpy (7)

Heat capacity / entropy / enthalpy, Ag–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location
Entropy printed: S	40.3 J/mol-atom/K	298.15	Ag2O alloy: O 0.333333	model	[1] Assal 1997 cites Kubaschewski 1993	Table IV, p. 6, row 3 report
Entropy printed: S	40.3 J/mol-atom/K	298.15	Ag2O alloy: O 0.333333	model	[1] Assal 1997	Table IV, p. 6, row 4 report
Entropy printed: S	40.5667 J/mol-atom/K	298.15	Ag2O alloy: O 0.333333	experimental	[1] Assal 1997 cites Pitzer 1937	Table IV, p. 6, row 1 report
Heat capacity printed: Cp	22.1 J/mol-atom/K	298.15	Ag2O alloy: O 0.333333	model	[1] Assal 1997 cites Kubaschewski 1993	Table IV, p. 6, row 3 report
Heat capacity printed: Cp	22.1 J/mol-atom/K	298.15	Ag2O alloy: O 0.333333	model	[1] Assal 1997	Table IV, p. 6, row 4 report
Heat capacity printed: Cp	21.8667 J/mol-atom/K	298.15	Ag2O alloy: O 0.333333	experimental	[1] Assal 1997 cites Pitzer 1937	Table IV, p. 6, row 1 report
Heat capacity printed: Cp	22.2667 J/mol-atom/K	298.15	Ag2O alloy: O 0.333333	experimental	[1] Assal 1997 cites Kobayashi 1951	Table IV, p. 6, row 2 report

Activity / EMF / Gibbs energy (5)

Activity / EMF / Gibbs energy, Ag–O system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Gibbs energy printed: Δ°G	-6887 J/mol		liquid Ag	experimental	[1] Assal 1997 cites Sieverts 1909	Table I, p. 2, row 1 report
Gibbs energy printed: Δ°G	-7028 J/mol		liquid Ag	experimental	[1] Assal 1997 cites Sieverts 1909	Table I, p. 2, row 1 report
Gibbs energy printed: Δ°G	-6975 J/mol	1348	liquid Ag	experimental	[1] Assal 1997 cites Donnan 1910	Table I, p. 2, row 2 report
Vapour pressure printed: PO2	5.370e7 Pa	803		model	[1] Assal 1997 cites Keyes 1922	p. 1 report	Using the silver-Ag2 O equilibrium measurements from Keyes and Hara,14 they could calculate the eutectic point (i.e., the intersection of these three equilibria) and found T 4 803 K and PO2 4 5.37 × 107 Pa.
Vapour pressure printed: PO2	5.260e7 Pa	803.6		model	[1] Assal 1997	p. 6 report	The calculated eutectic point is at T 4 803.6 K, PO2 4 5.26 × 107 Pa, and xO 4 0.2514.

Model expression (19)

Model expression, Ag–O system
Property	Value	Phases / composition	Class	Source	Location
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	5.98 J/mol/K	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Shah 1967	Table I, p. 2, row 6 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-14473 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Shah 1967	Table I, p. 2, row 6 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-14940 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Lupis 1968	Table I, p. 2, row 8 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	21.68 J/mol/K	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Lupis 1968	Table I, p. 2, row 8 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	18.04 J/mol/K	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Fischer 1966	Table I, p. 2, row 5 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-10463 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Fischer 1966	Table I, p. 2, row 5 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	21.22 J/mol/K	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Diaz 1966	Table I, p. 2, row 4 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-14145 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Diaz 1966	Table I, p. 2, row 4 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-15004 J/mol	liquid Ag alloy: O 0	model	[1] Assal 1997	Table I, p. 2, row 12 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	5.97 J/mol/K	liquid Ag alloy: O 0	model	[1] Assal 1997	Table I, p. 2, row 12 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-13904 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Parlee 1965	Table I, p. 2, row 3 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	5.41 J/mol/K	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Parlee 1965	Table I, p. 2, row 3 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	6.52 J/mol/K	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Otsuka 1981	Table I, p. 2, row 9 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-16140 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Otsuka 1981	Table I, p. 2, row 9 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-15614 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Magill 1988	Table I, p. 2, row 10 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	6.76 J/mol/K	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Magill 1988	Table I, p. 2, row 10 report
gibbs energy expression term printed: Δ°G (coefficient B of A + B·T)	5.79 J/mol/K	liquid Ag alloy: O 0	model	[1] Assal 1997	Table I, p. 2, row 11 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-14759 J/mol	liquid Ag alloy: O 0	model	[1] Assal 1997	Table I, p. 2, row 11 report
gibbs energy expression term printed: Δ°G (constant term A of A + B·T)	-17872 J/mol	liquid Ag alloy: O 0	experimental	[1] Assal 1997 cites Baker 1968	Table I, p. 2, row 7 report

Sources

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

Jérôme Assal, Bengt Hallstedt, Ludwig J. Gauckler, Thermodynamic Assessment of the Silver–Oxygen System, Journal of the American Ceramic Society 80, 3054-3060 (1997). doi:10.1111/j.1151-2916.1997.tb03232.x

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}
}