New materials from high-pressure experiments.

High-pressure synthesis on an industrial scale is applied to obtain synthetic diamonds and cubic boron nitride (c-BN), which are the superhard abrasives of choice for cutting and shaping hard metals and ceramics. Recently, high-pressure science has undergone a renaissance, with novel techniques and instrumentation permitting entirely new classes of high-pressure experiments. For example, superconducting behaviour was previously known for only a few elements and compounds. Under high-pressure conditions, the 'superconducting periodic table' now extends to all classes of the elements, including condensed rare gases, and ionic compounds such as CsI. Another surprising result is the newly discovered solid-state chemistry of light-element 'gas' molecules such as CO2, N2 and N2O. These react to give polymerized covalently bonded or ionic mineral structures under conditions of high pressure and temperature: the new solids are potentially recoverable to ambient conditions. Here we examine innovations in high-pressure research that might be harnessed to develop new materials for technological applications.