Quasi-elastic light scattering diffusion measurements of FeCl2·4H2O in glycerol

Diffusion of FeCl 2 ·4H 2 O in glycerol (0.4 M) is measured from 20 to 60°C through light scattering experiments. In this temperature range the solvent viscosity varies by a factor of 20. The scattering angle is varied from 30 to 150° to show the hydrodynamic q −2 behavior in the scattering wavevector q . Assuming a Stokes—Einstein relationship D = k B T /6πη R , the radius R = 2.05 ± 0.09 A is obtained for ferrous chloride.