Carbonaceous sulfur hydride (CSH) is a potential superconductor that was announced in October 2020 by the lab of Ranga Dias at the University of Rochester, in a Nature paper that was later retracted.
As of October 2020, the material's molecular structure remains uncharacterized, as extreme pressures and the light elements used are unsuitable for most measurements, such as X-ray determination.
[1] A starting compound of carbon and sulfur is synthesized with a 1:1 molar ratio, formed into balls less than five microns in diameter, and placed into a diamond anvil cell.
[1] Other researchers were skeptical that such materials could serve as room temperature superconductors, as the absence of van Hove singularities or similar peaks in the electronic density of states of more than 3000 candidate phases rules out conventional superconductivity.
[12] On 14 October 2020, a paper by Elliot Snider, et al. from the Dias lab was published, claiming that carbonaceous sulfur hydride was a room-temperature superconductor.
[1] additional criticism focused on the measurements of AC susceptibility[6] [23] used to test the superconductivity as the more definitive Meissner effect was too hard to observe at the scale of the experiments.