Inorganic Substances with Rubber-like Properties
Abstract Two inorganic substances with elasticity similar to that of rubber are described in the literature of the subject, viz., elastic sulfur and polyphosphonitrilic chloride. In this paper we shall deal with investigations of both. It is common knowledge that sulfur heated to 170° becomes highly viscous; if then cooled, e. g., by plunging into water, it yields an amorphous elastic product. If threads of this amorphous product are stretched, they show a double refraction, and, as Trilat has found, develop a fiber-diagram. With Go the author has examined this diagram, and deduced from it the following arrangement of the sulfur atoms: long chains of sulfur atoms, linked by strong homeopolar valences, are arranged parallel to the direction of stretching. Their special position in the elementary cell is shown in Fig. 1. In a recent publication, Warren has made it clear that ordinary sulfur is made up of 8-atom rings. The molecular weight of the elastic form Sn is not known, but seems to be very high. We know from earlier work that the melting of sulfur produces an equilibrium between the two forms, and this shifts, at higher temperatures, in favor of the chain-sulfur. About 1000 calories per gram atom S are consumed in the transformation of S8 into Sn.