Superconductor (IMAGE) Osaka University Caption (Left) Development of the superconducting transition temperature Tc. Hydrogen sulfide's highest Tc is H2S (150 GPa), and this is 30 K higher than what was previously the highest Tc superconductor � Cuprate, Hg-Ba2Ca2Cu3Oy -- and the lowest temperature ever recorded on the Earth's surface to date (184 K/-93�). Credit Osaka University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.