Polysulfur nitride, conductivity

In contrast to the nonconducting polymers, such as hdpe, polysulfur nitride (SN) is a conductor of electricity at ordinary temperatures, and this property is enhanced as the temperature is lowered. The polymer (SN) is an anisotropic superconductor at 0.3 K. This conductivity is related to a trans planar conformation of chains with delocalized it orbitals. 

Thiazanes are inorganic polymers like polyphosphazenes but with phosphorus atoms in the chain replaced by sulfur. They are electron-conducting covalent polymers that are analogous to solid polysulfur nitride. Electron-conducting polymers such as polythiazanes are too reactive for use in air because they are radicals a free unpaired valence electron or an electron hole is in chemical language a radical, and radicals happen to be very reactive. 

Sulfur nitride polymer (polysulfur nitride, polythiazyl) [-(SN)-]n. First synthesized in 1910 but ignored for six decades, this covalent polymer has been restudied and found to have the physical and electrical properties of a metal. It is formed by passing the vapor of (SN)4 over a catalyst that cracks it to (SN)2, which is condensed on a cold surface where it spontaneously polymerizes into crystalline form. The crystals are malleable and can be cold-worked into thin sheets or fibers under pressure, having an electrical conductivity similar to that of mercury, and superconducting near 0 K. 

A key discovery was made in 1973, when the inorganic polymer polysulfur-nitride (SN) was found to be a metal [1]. The conductivity of (SN) at room temperature is about 10 S cm" below a critical temperature of about 0.3 K, (SN) becomes a superconductor [2]. Unfortunately (SN), is explosive and no commercial application was possible. 

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