Une nouvelle forme de carbone, ultra-dure et transparente du cratère d'impact de Popigai en Russie
Abstract
A natural shockwave event led to the formation of a new crystalline polymorph of carbon in gneisses from the Popigai crater, Russia. The new species occupies the interior of a multiphase assemblage and is entirely enveloped by lonsdaleite and graphite. Polishing hardness of this new phase is greater than that of lonsdaleite. Micro-beam synchrotron X-ray diffraction, imaging and fluorescence studies revealed a pure transparent carbon phase. The diffraction pattern is indexed in terms of a cubic cell ( a=14.697 Å, space group Pm3m.). This species was neither encountered in static or dynamic high-pressure experiment nor predicted by theoretical calculations. To cite this article: A. El Goresy et al., C. R. Geoscience 335 (2003).
- Publication:
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Comptes Rendus Geoscience
- Pub Date:
- October 2003
- DOI:
- Bibcode:
- 2003CRGeo.335..889E
