The multiple signatures of carbon

Abstract

Car bon is the fourth most abundant element by mass in the universe after hydrogen, helium and oxygen. The chemistry of carbon is both ancient and ubiquitous, with applications ranging from fine jewellery to heating, textiles, pharmaceuticals, energy and electronics. How can we present this familiar stuff, which has played a central role in the history of chemistry, as an exemplar technoscientific object? Wouldn't it be more adequately described as a typical scientific object? To be sure, carbon is an object of 'pure research'. It emerged in the nineteenthcentury as a chemical substance, as an abstract albeit material substrate underlying a range of simple and compound bodies. However, this ontological perspective shows only one face of carbon. While scientific research was focused on what is conserved through change, the researchers' attention shifted to what might be changed: Carbon came back as a menagerie of allotropes-fullerenes, nanotubes, graphene and many more-which populate the 'nanoworld', making it a rich source of technological possibilities. The ontological status of carbon in a scientific perspective answers the question 'what is it?' while in a technoscientific approach, the question answered is rather 'what might be performed with it?' or, more precisely, 'what might it afford?' We could thus portray carbon as a Janus and contrast its scientific and technoscientific identities. 2 However, this contrast provides a far too purified image of carbon. Carbon has assumed so many guises over the course of the centuries that it almost seems to play various personae moving with a momentum of their own, inspiring new adventures while exhibiting surprising physical and chemical properties. Diamond, charcoal, graphite, carbon compounds, mephitic air and CO 2 are among the characters that have played-and continue to play-significant roles in science and mythology, in industry and economy alike. Carbon is too ubiquitous, too polymorphic and too important in our 1 Preprint (2014), reworked by the authors.