CATION DISTRIBUTION BY POWDER X-RAY-DIFFRACTION IN UVAROVITE-GROSSULARITE GARNETS SOLID-SOLUTIONS SYNTHESIZED BY THE SOL-GEL METHOD

Nominal compositions of uvarovite-grossularite solid-solutions Ca3(Cr1-xAlx)2Si3 O12, series x = 0 to x = 1, have been prepared by sol-gel method and fired up to 1000°C. Five of these structures (x = 0 to 0.5) have been refined using the Rietveld method from X-ray powder diffraction data taken with a Siemens D-500 diffractometer. The limit of solid solutions of these structures has been stabilized in 20% mole grossularite. The unit cell is cubic, Ia3d (230), Z = 8, a = 12.0205(5) to 11.9903(18) for the five structures presented. © 1994 Academic Press, Inc.