A Review of Sodium Fluoride Solubility in Water

The solubility of NaF in water is important to a number of industries, but there is a limited review of the large amount of solubility data scattered throughout the literature. The present study collected all of the data on the NaF solubility in water that could be found in the peer-reviewed literature between the temperature 0 and 100.6 °C (the upper temperature being approximately the boiling point of a saturated solution). Fifty-five solubility data points were found, collected from 29 studies. There was a large amount of scatter among the data, both across and within most studies. After screening out suspect data, the solubility of NaF was found to be a linear function of temperature, with a change of solubility of 0.003 molal per °C. Averaging the data at 25 °C provides an estimated solubility of 0.987 molal at that temperature.