Some applications of X-ray diffraction methods in industrial chemistry

Several examples of the use of X-ray diffraction patterns in industrial chemical problems are mentioned. The results include the identification of the constituents of "bleaching powder", the explanation of the variable colours of certain precipitated iron oxide pigments as a consequence of the polymorphism of FeO(OH), the identification of boiler scale constituents with known mineral species, a study of the crystallography of the hydrated calcium aluminates and of calcium sulphate sub-hydrate (hitherto known as "hemihydrate"), the quantitative analysis of mixtures of polymorphous crystal forms, the determination of crystal size in the range below 10 -5 cm., and the discovery of the molecular structure of plastics.