I. The crystal structures of wulfenite and scheelite. II. The crystal structures of sodium chlorate and sodium bromate

摘要

In the study of the crystal structures of wulfenite and scheelite a number of possible sources of difficulty came to light which either would not be encountered or could be avoided in the study of sodium chlorate by the Bragg method. Large crystals could be obtained without serious difficulty and on these any desired face could be ground, a necessary precaution that could not be taken with the borrowed specimens of the previous research. This would eliminate gross ambiguities as to the amount of absorption suffered by the X-ray beam, and also permit definition of the relative areas of crystal operating in the successive orders of reflection. On the interpretive side, although the various atoms involved differ in atomic number sufficiently for their effects to be easily distinguishable, they are all included within a sufficiently limited range so that their contributions to the amplitude of the reflected wave would be expected to be sufficiently near proportional to their atomic numbers. It seemed advisable to make measurements on sodium bromate also since this salt is completely isomorphous with the chlorate.