In 1999, Anisimov et al. conjectured superconductivity in nickelates, proposing nickel oxides as direct analogs to the cuprate superconductors. Superconductivity in an infinite-layer nickelate, Nd 0.8 Sr 0.2 NiO 2, was reported at the end of 2019 with a superconducting transition temperature between 9 and 15 K (−264.15 and −258.15 °C). This superconducting phase is observed in oxygen-reduced thin films created by the pulsed laser deposition of Nd 0.8 Sr 0.2 NiO 3 onto SrTiO 3 substrates that is then reduced to Nd 0.8 Sr 0.2 NiO 2 via annealing the thin films at 533–553 K (260–280 °C) in the presence of CaH 2. The superconducting phase is only observed in the oxygen reduced film and is not seen in oxygen reduced bulk material of the same stoichiometry, suggesting that the strain induced by the oxygen reduction of the Nd 0.8 Sr 0.2 NiO 2 thin film changes the phase space to allow for superconductivity. Of important is further to extract access hydrogen from the reduction with CaH 2, otherwise topotactic hydrogen may prevent superconductivity.