TEM study of incommensurate phases in minerals: implication for materials science

Incommensurate (INC) phases as a special, one-dimensional case of quasi-crystals were found in natural minerals of plagioclase and pyroxene solid solutions, as well as in quartz and in telluriumantimony (Sb2Te3). A relationship between the chemical composition of the mineral and its ability to be in the metastable state of INC was justified based on the transmission electron microscopic (conventional and high-resolution) data. Namely, the amphoteric elements adjacent to the large diagonal of amphoters of the Mendeleev table favor the formation and prolonged life-time of INC. Telluriumantimony proved to display the most pronounced INC state. Its features suggest that the red/ox transition provides the generation of energy in chemical systems.