The Electrical and Thermal Conductivity of Liquid Cesium to 1650 °C and the Critical Point of Cesium

The electrical resistivity of high purity liquid cesium was determined in a pressurized furnace from 600 to 3000°F (316 to 1649°C) by measurements of the electrical resistance of a Ta-10%W alloy tube, both empty and filled with cesium. The resistivity found for the lower temperatures agrees moderately well with previously published results, the discrepancy decreasing at the highest temperatures. The thermal conductivity of liquid cesium was calculated from its resistivity using a Lorenz number of 2.3 × 10⁻⁸ (V/deg K)². By comparing the cesium data with a reduced resistivity vs reduced temperature curve for mercury, the critical temperature of cesium is found to be 3190 °F (1754 °C), with a corresponding critical pressure of 130.8 atm from an available vapor-pressure correlation.