High pressure studies of (SN)x and S4N4

Abstract At high pressure S 4 N 4 and (SN) x thermally decompose to octameric S 8 plus nitrogen, or fibrous S x plus nitrogen, depending upon the magnitude of pressure. Measurements of the electrical conductivity as a function of temperature at high pressure indicated that (SN) x behaves metallically, and that the thermal decomposition process is associated with a sharp increase in resistance. S 4 N 4 , on the other hand, initially displays a semiconductor thermal behavior, but in excess of 30 to 35 kbar the decomposition is characterized by transient high conductance spikes as well as a turning point in the steady state resistance. The quenched product from the P-T decomposition boundary where the transients are observed is a black form of sulfur. The high conductance spikes are interpreted as due to a transitory metallic sulfur-nitrogen phase akin to (SN) x which exists until the nitrogen dissociates.