Characteristic densities of low- and high-pressure liquid SnI4

An in situ synchrotron x-ray absorption measurement was carried out to estimate the density of liquid SnI4. The characteristic densities of the low- and high-pressure liquids were found to be 4.6-4.7 and 4.9-5.0 g/cm3, respectively, and their region is separated at around 1.7 GPa. The difference in density, although a slight amount of 0.3-0.4 g/cm3, strongly suggests the existence of a weak but discontinuous phase transition at that pressure between the two liquid regions. (author)