Low-Frequency Dielectric Constant of LiF, NaF, NaCl, NaBr, KCl, and KBr by the Method of Substitution

The 1000-Hz 300°K dielectric constants of some alkali halides were measured to an accuracy of 0.01% by the method of substitution. Reproducibly different values for various crystals of the same type were obtained which varied beyond the experimental error. The ranges of results for various crystals of each type measured are LiF, 9.0355-9.0360; NaF, 5.0719-5.0722; NaCl, 5.8940-5.8956; NaBr, 6.3957-6.3974; KCl, 4.8112-4.8182; and KBr, 4.8735-4.8762. The spread for each type of crystal is thought to be attributable to random trace impurities. The numbers are discussed in the light of past values.