Chemists have finally synthesized 2D carbon compounds that promise exotic electronic properties — and that resisted scientists’ efforts to make them.

The most acclaimed 2D carbon compound is the wonder material graphene, which consists of a sheet of carbon atoms just one atom thick. These atoms are linked together in hexagonal structures called rings, and researchers have predicted the existence of other 2D carbon compounds made of a mixture of hexagonal and nonhexagonal rings. But such compounds have eluded synthesis because they are prone to rearranging their bonds to form the more stable hexagonal configuration.

Michael Gottfried at Philipps University Marburg in Germany and his colleagues made ribbons of two 2D carbon compounds with nonhexagonal rings: one compound whose rings had 5, 6 or 7 carbon atoms, and another whose rings had 4, 5, or 7 carbon atoms. The team achieved this by coupling building blocks atop a gold surface.

The authors suggest that the materials could have quantum applications and that the coupling process could be used to synthesize undiscovered forms of 2D carbon.