Diatomic sulfur: a mysterious molecule

Abstract

ABSTRACTDiatomic gaseous sulfur obtained in thermal processes of elemental sulfur dissociation and hydrogen sulfide decomposition is considered. It is shown that the thermodynamic parameters of this substance formation accepted in literature refer to its metastable singlet state . Since diatomic sulfur is an isoelectronic analog of oxygen, its ground state must be a triplet . As it turned out, this ground triplet state of S2 molecule can be obtained at low temperature catalytic decomposition of H2S. The reaction mechanism is considered in terms of non-equilibrium thermodynamics for open systems. The process occurs at room temperature due to internal energy of H2S molecules without using external energy sources. As shown, metal catalyst provides the capture and inter-conversion of energy from exothermic processes of adsorption and dissociation of H2S molecules resulted in their chemical transformation on the catalyst surface into the final reaction products - molecular hydrogen and diatomic triplet sulfur. Some properties of gaseous triplet sulfur and white solid globular sulfur obtained from its saturated aqueous solutions are considered. A hypothesis about the nature of bacterial sulfur S0 and possible mechanism of chemosynthesis of carbohydrates from H2S and CO2 is proposed.