Saturated vapour pressure and vapour density of fused thallous nitrate

The vapour pressure and vapour density of fused thallous nitrate have been measured, from 250 to 450°C, by the boiling point and the transpiration method respectively. Assuming the vapour to be monomeric, the vapour pressure is given by log10p(bar)= 5.66–6180/T. The volatility of fused thallous nitrate is intermediate between that of the alkali nitrates and of the nitrato compounds of Field and Hardy's classification. The heat and standard entropy of vaporization at the melting point are 118 ± 4 kJ/mol and 104 ± 4 J °K–1 mol–1, and are similar to those of the thallous halides. An increase in the covalent character of the Tl—O bond is thought to occur on vaporization.