The metal oxide bilayer deuterate (hydrate) Na0.3NiO2·1.3D2O (Na0.3NiO2·1.3H2O) were prepared from NaxNiO2 by extracting Na+ cations and simultaneously intercalating fully and nondeuterated water. High-resolution neutron powder diffraction, thermogravimetric analysis, and inductively coupled plasma atomic emission spectroscopy were used to show that a Na0.3(D2O)1.3 network separates layers of edge-sharing NiO6 octahedra.