The molar volumes and thermal expansion coefficients of solid and liquid potassium from 0–85°C

Abstract

The density of potassium in the range 0°–85°C has been measured by the classical pyknometric method with a precision better than 0.01%. Expressions are given for the solid and liquid molar volumes as functions of temperature, and the expansion on melting. The freezing-point curve for the specimen indicated a content of impurities insoluble in the solid phase but soluble in the liquid phase of no more than 0.002%. The effect of such impurities on the thermal expansion coefficient and the compressibility is evaluated and shown to become very large as the melting-point is closely approached.