Abstract :
[en] Ti-spessartite, Ti-andradite and its indium homolog, Ca<inf>3</inf>In<inf>2</inf>(Si, Ti)<inf>3</inf>O<inf>12</inf>, have been synthesized and investigated by infrared (ir) spectroscopy. The use of isotopic species (<sup>46</sup>Ti-<sup>50</sup>Ti) gives the unequivocal proof that some of the additional bands observed in the 800-600 cm<sup>-1</sup> region are due to TiO<inf>4</inf> tetrahedra. For Si-Ti replacements up to 10 mol%, the localization of Ti on the available tetrahedral sites depends on the nature of the cations. For the In garnet all (or nearly all) Ti is located on tetrahedral sites; in Ti-andradite Ti is distributed over tetrahedral and octahedral sites, tetrahedral sites being thus occupied, in part by Ti (ir band near 700 cm<sup>-1</sup>) and in part by Fe (ir band near 650 cm<sup>-1</sup>); and Ti-spessartite the presence of Ti on tetrahedral sites is doubtful, these sites being essentially occupied by Al. © 1979 Springer-Verlag.
Scopus citations®
without self-citations
24