Carbon can arrange itself into one of the hardest materials in nature, or into one so soft that children inscribe trails of it on paper. Several decades ago, scientists started wondering: Aside from diamond and graphite, what other crystalline forms might carbon take?
In 1985, they had their first answer. A group of chemists discovered little hollow spheres constructed of 60 carbon atoms that they dubbed buckminsterfullerenes, or buckyballs or fullerenes for short. (The crystals resembled geodesic domes, popularized by the architect R. Buckminster Fuller.) A new field of chemistry sprang up around the nanometer-wide spheres, as researchers raced to discover properties and applications of what’s been called the most beautiful molecule.
Bigger fullerenes were found. Then, a few years later, a paper by the Japanese physicist Sumio Iijima sparked interest in a related carbon form, initially dubbed buckytubes but now known as carbon nanotubes: hollow cylinders made of a honeycomb lattice of carbon atoms that’s rolled up like a toilet paper tube.
The carbon crystals had a spectrum of electrical, chemical and physical properties that no other element seemed to match. Excitement around carbon nanoscience was cranked still higher when three of the discoverers of buckyballs, Robert Curl, Harold Kroto and Richard Smalley, received the 1996 Nobel Prize in Chemistry. Then in 2004, the physicists Andre Geim and Konstantin Novoselov found a way to isolate flat sheets of carbon atoms — a crystal known as graphene — igniting another explosion of research that has sustained itself ever since, and earning themselves the 2010 physics Nobel.
Recently, chemists discovered yet another type of carbon crystal — this time, to much less fanfare. Most of the carbon experts contacted for this story still hadn’t heard of it. And so far, the entire global supply probably amounts to milligrams, about the mass of a handful of house flies.
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