Elton Santos, from Queen’s University Belfast (www.qub.ac.uk), reports that scientists have found a way to make carbon both very hard and very stretchy by heating it under high pressure.

This “compressed glassy carbon”, developed by researchers in China and the USA, is also lightweight and could potentially be made in very large quantities, so it could be used for numerous applications — ranging from bullet-proof vests to new kinds of electronic devices.

Carbon is a special element because of the way its atoms can bond with each other in different ways to form different structures.

When the researchers squeezed several sheets of graphene together at high temperatures, they found that certain carbon atoms were exactly in the right position to form what are known as sp3 bonds between the layers.

Scientists found that just over one in five of all bonds were sp3, which means that most of the atoms are still arranged in a graphene-like structure.

Over the small scale of individual graphene sheets, the atoms are arranged in an orderly hexagonal pattern, but on a larger scale, the sheets are arranged in a disorderly fashion — and it is probably this structure that gives the material the combined properties of hardness and flexibility.