CONTRIBUTIONS ON THE THERMAL-BEHAVIOR OF SULFATES .16. THE CHEMICAL-VAPOR TRANSPORT OF GA-2(SO4)(3) WITH CL-2 AND HCL - EXPERIMENTAL RESULTS AND CALCULATIONS

Crystals of anhydrous Ga-2(SO4)(3) can be grown by means of CVT (e.g. 525 degrees C --> 475 degrees C) in the less hot region of a closed si lica ampoule. We investigated the dependance of the deposition rate on the concentration of the transport agent (Cl-2, HCl) and the transpor t temperature (475 degrees C less than or equal to ($) over bar T less than or equal to 750 degrees C; T-2 > T-1; Delta T = 50 degrees C; ($ ) over bar T = 0.5(T-1 + T-2)). Experimental results and thermodynamic calculations on the basis of Delta(F)H degrees(298)(Ga-2(SO4)(3)) = - 686.5 kcal/mol show a good agreement.