# Ca2SiO4: enthalpy of formation > Enthalpy of formation of Ca2SiO4: 8 literature value(s) with sources, pages and quotes, from ORCHID. HTML: https://data.orchid-project.org/compounds/Ca2SiO4.html · Markdown: https://data.orchid-project.org/compounds/Ca2SiO4.md 8 accepted literature formation-enthalpy value(s) (model 8). Systems: [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) ## Literature values Table: Enthalpy of formation of Ca2SiO4 reported in the literature (8) | Value | Phase as printed | T (K) | Class | Method | System | Source | Location | Quote | |---:|---|---:|---|---|---|---|---|---| | -2548 kJ/mol (basis unstated) | α-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023; _cites Haas 1981_ [doi](https://doi.org/10.1063/1.555645) | Table 7, p. 8, row 12; `ORC-QQR4UGT3GS.ad28d4` | | | -2316 kJ/mol (basis unstated) | γ-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023 | Table 7, p. 8, row 17; `ORC-N4E76HFI6M.5129ec` | | | -2316 kJ/mol (basis unstated) | γ-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023; _cites Haas 1981_ [doi](https://doi.org/10.1063/1.555645) | Table 7, p. 8, row 18; `ORC-RFZ5DTDIVY.160aa4` | | | -2307 kJ/mol (basis unstated) | β-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023 | Table 7, p. 8, row 15; `ORC-ETBEBYX5XW.89fdb7` | | | -2306 kJ/mol (basis unstated) | β-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023; _cites Haas 1981_ [doi](https://doi.org/10.1063/1.555645) | Table 7, p. 8, row 16; `ORC-3QNEW2TV5R.e38ae3` | | | -2304 kJ/mol (basis unstated) | α′-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023 | Table 7, p. 8, row 13; `ORC-DOD36BIQRQ.dd12cd` | | | -2293 kJ/mol (basis unstated) | α-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023 | Table 7, p. 8, row 11; `ORC-AMXBRCNROZ.9789a9` | | | -2198 kJ/mol (basis unstated) | α′-Ca2SiO4 | 298.15 | model | | [Ca–O–Si](https://data.orchid-project.org/systems/CA-O-SI.html) | [1] Abdul 2023; _cites Haas 1981_ [doi](https://doi.org/10.1063/1.555645) | Table 7, p. 8, row 14; `ORC-PBAHCHHFYE.0275fc` | | ### Uncertainty budget Components kept separate, in the value's unit (literature [SCHEMA.md](https://data.orchid-project.org/literature/SCHEMA.md), [UNCERTAINTY_CALIBRATION.md](https://data.orchid-project.org/literature/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. Table: Uncertainty budget of the literature values of Ca2SiO4 | Value | Unit | Printed | Reading | Method (class, basis) | Composition | Scatter | Conversion | Effective | |---:|---|---:|---:|---|---:|---:|---:|---:| | -2548 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | | -2316 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | | -2316 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | | -2307 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | | -2306 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | | -2304 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | | -2293 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | | -2198 | kJ/mol (basis unstated) | | 0.05 | 27.3 (model_calculated, calibrated) | | | | 27.3 | ## Sources 1. Wahab Abdul, Chancel Mawalala, Alexander Pisch, Marcus Nigel Bannerman, CaO-SiO2 assessment using 3rd generation CALPHAD models, Cement and Concrete Research 173, 107309 (2023). [doi:10.1016/j.cemconres.2023.107309](https://doi.org/10.1016/j.cemconres.2023.107309) ## 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-Parity: DFT-vs-experiment formation-enthalpy benchmark (version 2026.10; Version 1, machine-extracted), Zenodo (2026). https://doi.org/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). 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); 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. ```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_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} } ``` --- 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/).