Static and Dynamic Disorder in Metastable Phases of Tin Oxide

The multistage transformation of Sn3O4 to SnO2 in an oxygen-free atmosphere has been studied using hydrothermally synthesized samples, both pristine and heated, with in situ X-ray diffractometry, Raman spectroscopy, differential scanning calorimetry, dielectric spectroscopy, and ex situ X-ray photoelectron and nuclear magnetic resonance spectroscopies. Experimental evidence consistently shows that, beginning from 2,50 degrees C, Sn3O4 converts to Sn2O3 and, from 350 degrees C, to SnO2, accompanied by the formation of metallic tin. These two stages are associated with frequency-dependent dielectric losses, as revealed by impedance measurements, which also indicate a significant conductivity of 1.78 eV in activation energy. It is speculated that the relaxation-like processes relate to the transition from static to dynamic disorder and then to order in the oxygen sublattice.