Mixed layering in disordered Sri Lanka graphite

Abstract

Rotational disorder is common to two millimeter-sized samples of Sri Lanka disordered graphite which also contains domains of the new carbon phase. Chemical disorder in the samples is inferred from d 002 interplanar and lattice fringe spacings that are part of three distinct populations, centered at about d 002 = 0.348 nm, 0.371 nm, and 0.45 nm and from short-range periodic stacking in lattic-fringe ribbons. The aromatic and alicyclic structures form metastable carbon-rich sheets with variable (100 × C) (C + H + O + N) ratio. The chemical and structural data are consistent with a model of mixed-layered carbon-rich, C—(H,O,N), material. Mixed-layered carbons include previously reported carbynes which are re-interpreted as carbon-rich, pre-graphitic C—(H,O,N) material. Mixed layering of chemically impure, carbon-rich pre-graphite sheets reflects complex interactions of physical and chemical parameters during carbonisation and graphitisation of natural terrestrial carbonaceous material.