Squeezing hydrogen sulfide to extreme pressures results in a sulfur hydride phase that exhibits superconductivity at a record-setting 203 K, according to a team led by Alexander P. Drozdov and Mikhail I. Eremets of Germany’s Max Planck Institute for Chemistry (Nature 2015, DOI: 10.1038/nature14964). Discovered just over a century ago, superconductors are a small group of materials that conduct electricity without losing energy in the form of heat. Such materials could be used to make energy-efficient electric motors and power distribution systems. Most superconductors, however, exhibit that property only when they are chilled below an impractically low critical transition temperature (Tc). The hydride’s Tc is roughly 70 K warmer than that of the previous record holder, a copper oxide containing mercury, calcium, and barium. The analysis shows that as the researchers compressed H2S to gigapascal pressures, the sulfide decomposed, yielding elemental sulfur and H3S, the hydride responsible for the observed superconductivity. The finding confirms theoretical predictions that simple covalently bonded hydrogen-rich compounds can exhibit remarkably high Tc values and raises hopes for finding simple room-temperature superconductors.