Squeeze nickel oxide hard enough and it reverts to a metallic, electrically conducting phase, according to results from Carnegie Institute of Science. “Physicists have predicted for decades that the nickel oxide would transition from an insulator to a metal under compression, but their predictions have not previously been confirmed,” says team leader Viktor Struzhkin. 240 gigapascals is enough to convert micrometer-thin crystal samples of the oxide into a conducting phase. At that pressure electrical resistance drops by three orders of magnitude indicating a shift from semiconducting oxide to a metallic state. The discovery adds to our theoretical understanding of such changes and could ultimately allow materials scientists to design specific characteristics into novel substances.