Is La₃Ni₂O_6.5 a Bulk Superconducting Nickelate?

Superconducting states onsetting at moderately high temperatures have been observed in epitaxially stabilized RENiO₂-based thin films. However, recently, it has also been reported that superconductivity at high temperatures is observed in bulk La₃Ni₂O_7-δ at high pressure, opening further possibilities for study. Here we report the reduction profile of La₃Ni₂O₇ in a stream of 5% H₂/Ar gas and the isolation of the metastable intermediate phase La₃Ni₂O_6.45, which is based on Ni²⁺. 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.