OXIDATION OF CASI2 LAYERED CRYSTALS WITH COCL2 SOLUTIONS

A layer-structured crystal CaSi2 was found to be oxidized with CoCl2 a queous solutions. The CO2+ ions of the solution were reduced to metal at the edge surface of the crystals, while the interlayer calcium atom s of the crystals were removed as cations into the solution. A large a mount of hydrogen was evolved during the reaction, which was attribute d to a reduction product of water with a reactive silicon network gene rated by the deintercalation of calcium from CaSi2. The saturation mag netization of the cobalt metal deposited on the surface increased as t he reaction proceeded, approaching that of the bulk metal. The oxidati on mechanism of the CaSi2 is discussed on the basis of the chemical an alysis data.