Sur quelques nouvelles phases de formule NaxMnO2 (x ⩽ 1)

Several new ternary oxides have been isolated in the manganese-oxygen-sodium system for NaMn ⩽ 1: Na0.20MnO2, Na0.40MnO2, Na0.44MnO2, Na0.70MnO2+y (0 ⩽ y ⩽ 0.25) and NaMnO2, both with two allotropic varieties. All structures are characterized by edge sharing (MnO6) octahedra, forming double or triple chains for small sodium content and bidimensional layers when the NaMn ratio becomes close to 1. Electrical and magnetic behaviour of the phases has been determined.