Abstract
Superconducting states onsetting at moderately high temperatures have been observed in epitaxially stabilized RENiO(2)-based thin films. However, recently, it has also been reported that superconductivity at high temperatures is observed in bulk La(3)Ni(2)O(7-δ) at high pressure, opening further possibilities for study. Here we report the reduction profile of La(3)Ni(2)O(7) in a stream of 5% H(2)/Ar gas and the isolation of the metastable intermediate phase La(3)Ni(2)O(6.45), which is based on Ni(2+). Although this reduced phase does not superconduct at ambient or high pressures, it offers insights into the Ni-327 system and encourages future study of nickelates as a function of oxygen content.