Synthesis and structure of the monolayer hydrate K0.3CoO2·0.4H2O

The monolayer hydrate (MLH) K0.3CoO2·0.4H2O was synthesized from K0.6CoO2 by extracting K+ cations using K2S2O8 as an oxidant and the subsequent intercalation of water between the layers of edge-sharing CoO6 octahedra. A hexagonal structure (space group P63/mmc) with lattice parameters a=2.8262(1) Å, c=13.8269(6) Å similar to the MLH Na0.36CoO2·0.7H2O was established using high-resolution synchrotron X-ray powder diffraction data. The K/H2O layer in the K-MLH is disordered, which is in contrast to the Na-MLH. At low temperatures metallic and paramagnetic behavior was found.