# Th system > Th system: 11 accepted literature values (invariant reaction 5, heat capacity / entropy / enthalpy 2, formation 2, phase transition 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/TH.html · Markdown: https://data.orchid-project.org/systems/TH.md 11 accepted literature values from 3 paper(s) (experimental 4, model 7); 0 calculated phase diagram(s). 5 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/TH.json) · [CSV](https://data.orchid-project.org/systems/TH.csv) · [interactive explorer](https://orchid-project.org/data-explorer/#TH) · [papers (bibliography)](https://data.orchid-project.org/bibliography/pages/systems/TH.html) · [Markdown](https://data.orchid-project.org/systems/TH.md) Table: Accepted values by evidence class | Evidence class | Values | |---|---:| | experimental | 4 | | model | 7 | Table: Accepted values by property group | Property group | Values | |---|---:| | invariant reaction | 5 | | phase transition | 2 | | formation | 2 | | heat capacity / entropy / enthalpy | 2 | ## Invariant reactions (literature) Table: Invariant reactions reported in the literature for the Th system (5) | T (K) | Reaction / phases | Compositions (mole fraction) | Class | Source | Location | Quote | |---:|---|---|---|---|---|---| | 2028.15 | congruent melting: L \<-> βTh | L: Th 1 | experimental | [1] Wang 2008; _cites Palenzona 1989_ [doi](https://doi.org/10.1016/0022-5088%2889%2990170-7) | Table 2, p. 3, row 2; `ORC-2IUKTQ33P7` | | | 2028.15 | congruent melting: L -> βTh | L: Th 1 | experimental | [1] Wang 2008; _cites Palenzona 1989_ [doi](https://doi.org/10.1016/0022-5088%2889%2990170-7) | Table 4, p. 5, row 23; `ORC-5GAP5H6637` | | | 2028.15 | congruent melting: L \<-> βTh | L: Th 1 | experimental | [1] Wang 2008; _cites Thomson 1966_ [doi](https://doi.org/10.1016/0022-5088%2866%2990101-9) | Table 2, p. 3, row 1; `ORC-ZCTAKJM3IN` | | | 2022.65 | congruent melting: L \<-> βTh | L: Th 1 | model | [1] Wang 2008 | Table 2, p. 3, row 3; `ORC-7HD5OKFDVA` | | | 2022.65 | congruent melting: L -> βTh | L: Th 1 | model | [1] Wang 2008 | Table 4, p. 5, row 24; `ORC-YM4UCLPEAH` | | ## 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, Th system (2) | Phase | Compound | Value | T (K) | Class | MP DFT (kJ/mol-atom) | OQMD DFT (kJ/mol-atom) | Source | Location | Quote | |---|---|---:|---:|---|---:|---:|---|---|---| | α-Th | | 0 kJ/mol-atom | 298.15 | model | | | [2] Beneš 2014 | Table 1, p. 2, row 1; `ORC-NQ56VCOXGN.fa325a` | | | β-Th | | 9.9655 kJ/mol-atom | 298.15 | model | | | [2] Beneš 2014 | Table 1, p. 2, row 2; `ORC-DLRD757BQF.5ef82f` | | ## Other properties ### Phase transition (2) Table: Phase transition, Th system | Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote | |---|---:|---:|---|---|---|---|---| | Phase transition | 1633.15 K | 1633.15 | polymorphic: βTh -> αTh; _βTh: Th 1_ | experimental | [3] Liu 2009; _cites Okamoto 1991_ | Table 7, p. 6, row 10; `ORC-H52OINMVCF` | | | Phase transition | 1633.15 K | 1633.15 | polymorphic: βTh -> αTh; _βTh: Th 1_ | model | [3] Liu 2009 | Table 7, p. 6, row 11; `ORC-Z433FBLQEU` | | ### Heat capacity / entropy / enthalpy (2) Table: Heat capacity / entropy / enthalpy, Th system | Property | Value | T (K) | Phases / composition | Class | Source | Location | Quote | |---|---:|---:|---|---|---|---|---| | Entropy; _printed: S0(298.15)_ | 51.8 J/mol-atom/K | 298.15 | α-Th; _alloy: Th 1_ | model | [2] Beneš 2014 | Table 1, p. 2, row 1; `ORC-NQ56VCOXGN.00c88d` | | | Entropy; _printed: S0(298.15)_ | 63.028 J/mol-atom/K | 298.15 | β-Th; _alloy: Th 1_ | model | [2] Beneš 2014 | Table 1, p. 2, row 2; `ORC-DLRD757BQF.0b9f3c` | | ## Sources Reporting papers the values were read from (a value cited from another work names that work in its row). 1. C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008). [doi:10.1016/j.jallcom.2007.03.003](https://doi.org/10.1016/j.jallcom.2007.03.003) 2. O. Beneš, D. Manara, R.J.M. Konings, Thermodynamic assessment of the Th–U–Pu system, Journal of Nuclear Materials 449, 15-22 (2014). [doi:10.1016/j.jnucmat.2014.02.001](https://doi.org/10.1016/j.jnucmat.2014.02.001) 3. X.J. Liu, S.L. Wang, C.P. Wang, Thermodynamic assessments of the Sc–M (M: Ag, B and Th) systems, Journal of Alloys and Compounds 469, 186-192 (2009). [doi:10.1016/j.jallcom.2008.02.018](https://doi.org/10.1016/j.jallcom.2008.02.018) ## 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). https://doi.org/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). 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); 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. ```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_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=\, carrying only the record id, source and value; [how to contribute](https://orchid-project.org/contribute/).