Crystallization of BaxSr1-x(NO3)(2) solid solutions from aqueous solutionsand the influence of Ba2+ ion on Sr(NO3)(2) crystals

A series of BaxSr1-x(NO3)(2) crystals have been grown from aqueous solution s with different initial Ba2+/Sr2+ ratios. These crystals were characterize d by powder X-ray diffraction. All diffraction data were well indexed accor ding to the simple cubic structure, and the variation of lattice constants with the concentration of Ba2+ in the crystals accorded quite well to Vegar d's Law. The composition of the Sr(NO3)(2) crystal doped with Ba2+ was stud ied with an electron microprobe. It was found that Ba2+ was enriched in the 100 sectors. The quality of the crystals with different composition. estim ated by the high-resolution X-ray diffraction indicated that the second cat ion added to the crystalline phase degrades the crystalline quality of the crystals. Equilibrium behavior in the Ba(NO3)(2)-Sr(NO3)(2)-H2O system was analyzed using Lippmann's phase diagram, and the equilibrium distribution c oefficient D-Ba = 769.2. This large value of D indicates that the Ba2+ ion is drastically preferentially partitioned towards the solid phase. (C) 2001 Elsevier Science Ltd. All rights reserved.