By using a special form of target, the $K{\beta }_1$ lines in the spectrum of the secondary x-radiation from a series of alkali halides and some alkaline earth sulphides have been measured. Combining the results with Stelling's values for the $K$ absorption edges one readily finds values for the electron affinities of ${\mathrm{Cl}}^{-}$ and ${\mathrm{S}}^{--}$ and for the ionization potentials of ${\mathrm{K}}^{+}$ as they exist in the respective crystals. Pauling's theory is used to reduce these values to those for the free ions. Good agreement with other data is obtained in the case of the chlorides, fair agreement in the case of the potassium compounds, and poor results in the case of sulphur. Possible causes for these discrepancies are suggested. The general method used in this work to obtain the spectra of compounds may find useful application in methods of chemical analysis by means of x-ray spectra.

• Received 20 April 1935

DOI:https://doi.org/10.1103/PhysRev.47.896