Graphene, that magical one atom thick layer of carbon that has so many interested properties is made by a repeating pattern of six carbon atoms foreign hexagons. Now researchers at the Virginia Commonwealth University have discovered another form of graphene where the layer is composed by repeated pentagon patterns. They called it penta-graphene.
The new patterns is similar to the one found in some streets in Cairo, Egypt, and has been found to be thermally and mechanically stable. Indeed, it was by seeing a reproduction of these patterns on a photo of Cairo's streets (seen in Beijing) that Qian Wang, a professor at Beijing University and adjunct professor at VCU got the inspiration and decided to work on it.
Most of the work has been done through computer simulation and the researchers are still scratching their heads to find a practical way to fabricate penta-graphene. Interestingly, whilst the hexagonal form of graphene is conductive, the penta-graphene is a semi-conductor.
Another peculiar and counter interactive property of penta-graphene is the way it stretches. If you take a fabric and you stretch it in one direction it gets shorter (shrinks) in the other. That is exactly what happens to a hexagonal graphene, However, in case of the pentagonal graphene if you stretch it in one direction it stretches also in the other!
What I really find interesting is the ability we have got (I mean, scientists have got) to design new materials at the computer and then move on to lab's benches to actually create it. They are basically playing with molecules like with Lego bricks!