SYNTHESIS AND THERMAL PHASE CHANGES OF CRYPTOMELANE WITH DIFFERENT OCCUPANCY OF K-IONS.

Abstract

We conclude in the present paper that the difference in thermal decomposition behaviors of cryptomelanes depends on the occupancy of K-ions in its one-dimensional tunnels. For this work, cryptomelane with 50% (KMn//8O//1//6) and that with 100% occupancy (K//2Mn//8O//1//6) of K-ions are synthesized by using flux method and solid state reaction, respectively. The thermal decomposition behaviors of specimens are examined by DTA and TGA technique. Precipitated phases quenched from the established temperatures are identified by X-ray powder diffraction method.