The Relative Thermodynamic Stability of Diamond and Graphite

• Type: Article in International Scientific Journal
• Date: 2021

Authors

White, MA (Author) Other; Kahwaji, S (Author) Other; Vera L S Freitas (Author) FCUP; Siewert, R (Author) Other; Weatherby, JA (Author) Other; Maria D M C R Ribeiro da Silva (Author) FCUP; Verevkin, SP (Author) Other; Johnson, ER (Author) Other; Zwanziger, JW (Author) Other

Journal

Title: Angewandte Chemie - International Edition

Vol. 60

Pages: 1546-1549

ISSN: 1433-7851

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 11 Citations

Other information

Authenticus ID: P-00S-ZNF

DOI: 10.1002/anie.202009897

Abstract (EN): Recent density-functional theory (DFT) calculations raised the possibility that diamond could be degenerate with graphite at very low temperatures. Through high-accuracy calorimetric experiments closing gaps in available data, we reinvestigate the relative thermodynamic stability of diamond and graphite. For T400 K, graphite is always more stable than diamond at ambient pressure. At low temperatures, the stability is enthalpically driven, and entropy terms add to the stability at higher temperatures. We also carried out DFT calculations: B86bPBE-25X-XDM//B86bPBE-XDM and PBE0-XDM//PBE-XDM results overlap with the experimental -T Delta S results and bracket the experimental values of Delta H and Delta G, displaced by only about 2x the experimental uncertainty. Revised values of the standard thermodynamic functions for diamond are Delta H-f(o)=-2150 +/- 150 J mol(-1), Delta S-f(o)=3.44 +/- 0.03 J K-1 mol(-1) and Delta(f)G(o)=-3170 +/- 150 J mol(-1).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4