When you compress most materials, you squash their atoms or molecules up against each other, shortening the bonds between them. But a new kind ultra-compressible material acts like a set of gears and springs that shrink in size. Researchers from the Molecular Materials Group at the University of Sydney have created a series of new materials that deform using a kind of torsional mechanism that you can see in the gif above. The material's made up from two different metallic molecules — one lanthanide-based (LnN6) and the other iron-based (FeC6) — which are connected by cyanide bridges. When exposed to pressure, they collapse in on themselves, as PhysOrg explains:
The LnN6 units acting like torsion springs are synchronised by rigid Fe(CN)6 units acting like gears. The LnN6 twists away from its original trigonal prismatic geometry becoming octahedral. These LnN6 units act as torsional centres that coil dramatically under pressure and enable extreme compressibility in combination with chemical and thermal stability for the first time.
The material compresses by around 20 per cent in volume at 1GPa, which is "one of the largest known pressure responses for any crystalline material", according to Vanessa Peterson, one of the researchers, in a press release. The research is published in Nature Chemistry.
The team reckons it should be able to tweak the properties, by using different metallic and bridging molecules, to create new kinds of highly compressible materials that also provide other useful properties — such as porosity or chemical functionality. Exactly what those materials will end up like, though, remains to be seen.
Animated gif via the Molecular Materials Group at the University of Sydney