CONTRIBUTIONS ON THE THERMAL-BEHAVIOR OF SULFATES .11. ON THE CHEMICAL-VAPOR TRANSPORT OF FE2(SO4)3 WITH HCL - THERMOCHEMICAL CALCULATIONS AND EXPERIMENTAL RESULTS

Using HCl as a transport agent, well-shaped crystals of rhombohedral F e2(SO4)3 with edge length up to 1 mm were formed in the less hot zone of a silica ampoule. The dependence of the deposition rate on the mean transport-temperature for a constant concentration of the transport a gent (C = 4.5 x 10(-2) mmol HCl/cm3) shows a distinct maximum at TBAR = 560-degrees-C. Additionally, the influence of the concentration of t he transport agent at a constant temperature gradient was investigated . On the basis of thermochemical calculations, an explanation of the o bserved transport behaviour is given in the present paper.