From glassy carbon to mixed carbon

Materials Science Forging one of the world's hardest materials (diamond) from the same atomic carbon building blocks as one of its softest (graphite) has intrigued many a high school chemistry student. This dexterity of carbon originates from its ability to exist in two distinct bonded states, sp3 and sp2. Materials in which these two states coexist are highly sought after by materials scientists. Hu et al. report that forging glassy carbon at moderate temperatures yields a series of sp3-sp2 hybrids that possess unusual property combinations. X-ray diffraction, electron microscopy, and electron energy-loss spectroscopy revealed that compression induces local buckling of sp2-bonded graphene sheets through sp3 nodes to form graphene networks with long-range disorder and short-range order. The study defines a roadmap for creating bulk carbon-based materials with previously unachievable property combinations. Sci. Adv. 10.1126/sciadv.1603213 (2017).