Abstract
It is shown that careful preparation is necessary to achieve a consistent value for the Cl35 nuclear quadrupole resonance frequency in KClO3 samples at 273.16 °K (the triple point of water). This is illustrated by measurements on a number of samples. It is suggested that the N.Q.R. frequency of Cl35 in KClO3 at 273.16 °K and atmospheric pressure is 28,213,372 ±2 Hz. This value is compared with measurements made by previous workers which show a considerable spread.