SYNTHESIS AND STRUCTURE OF RARE-EARTH AND INDIUM TELLURATES R2TEO6

A series of previously unreported rare-earth tellurates with the general formula R2TeO6 has been prepared by solid-state reaction at elevated temperatures. The X-ray diffraction patterns of these compounds were indexed on the basis of a hexagonal unit cell and the unit cell dimensions were calculated. The Y, La and Pr through Tm compounds form an isomorphous series, while the Sc, In and Lu tellurates are of different structure. A linear relationship exists between the lattice constants and the ionic radius of the trivalent cations which demonstrates the lanthanide contraction in these compounds. © 1968.