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Media Opportunity: Dalhousie chemist solves enduring question over stability of graphite vs. diamond with answer that will require modifications to school chemistry textbooks

For decades, scientists have studied and debated which of the two most important forms of elemental carbon -- diamond or graphite -- was more stable.

When they finally agreed that graphite had greater stability except when under high pressure, the matter seemed settled at long last. But recent calculations questioned that finding. Now, research out of Dalhousie University has definitively settled the matter.

Mary Anne White, OC, PhD, a Dalhousie chemist and Fellow of the Royal Society of Canada, led the study and collaborated with colleagues in the university’s Faculty of Science and five research groups in three countries.

The team determined that our previous understanding of the relative stability of graphite and diamond had significant gaps. The main finding, just published in a leading journal from the German Chemical Society, Angewandte Chemie, was that without applied pressure, graphite is more stable than diamond for all temperatures below 400 Kelvin or 127 ^oC, down to absolute zero.

Their findings mean that modifications will need to be made to chemistry textbook numbers that underpin the accurate prediction of many chemical reactions and properties. The knowledge is vital to understanding how elements form different structures like diamond and graphite, which we know are used in such things as odour-eating insoles and lithium-ion batteries.

Dr. White is available to explain the significance of her research, which included burning diamond powder by lighting each tiny crystal with an electrical spark in a sealed container to determine the heat of combustion.

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Media Contact:
Alison Auld
Senior Research Reporter
Dalhousie University
Cell: 1-902-220-0491
Email: alison.auld@dal.ca