The team started with a substance called 5,6,11,12-tetrachlorotetracene (with the formula C18H8Cl4) – a carbon-based molecule that looks like a row of four honeycomb cells flanked by four chlorine atoms hovering around like hungry bees. Sticking a thin layer of the material to a cold, salt-crusted piece of copper, the researchers drove the chlorine-bees away, leaving a handful of excitable carbon atoms holding onto unpaired electrons in a range of related structures. Two of those electrons in some of the structures happily reconnected with each other, reconfiguring the molecule's general honeycomb shape. The second pair were also keen to pair...
