The structure of cold condensed lead chloride (PbCl₂)

Abstract

When lead chloride is deposited onto substrates at temperatures below 150 K, a non‐crystalline film is formed. This material crystallizes at temperatures above 260 K, as could be demonstrated by UV‐VIS‐spectroscopy. In order to determine whether or not the deposited material consists of extremely small crystals with a high degree of disorder or of a genuine amorphous phase, it was investigated by electron diffraction. We describe the procedure which we applied for the determination of the elastically scattered intensity as a function of the scattering vector. From this function, the reduced radial distribution function was determined. The results were compared with those reported about crystalline and molten lead chloride. The short range order in the cold condensed material is different from that in the crystal and that in the melt. Hence, cold condensation of lead chloride leads to the formation of an ionic glass.