LOCAL INTERCONVERSIONS BETWEEN GRAPHITE AND DIAMOND STRUCTURES

Chemically favorable local defects in the graphite lattice converting trigonally hybridized carbon atoms into tetrahedrally hybridized atoms connecting parallel layers are considered from a systematic viewpoint . Vice versa, local defects in the diamond net converting tetrahedrall y hybridized carbon atoms into trigonally hybridized atoms without giv ing rise to polyradicals are examined. Some of these local transitions interconverting the two main allotropes of carbon may already occur i n reality; the most likely are considered to be either the formation o r the rupture of bridges between graphitic sheets involving (1) six el ectrons, analogous to the Diels-Alder reaction, and (2) pairs of 1,3-b onds between benzenoid rings. (C) 1997 Elsevier Science Ltd. All right s reserved.