Incorporation of Th4+ into ivanyukite crystal structure
The article contains information about the natural ivanyukite variety containing up to 30 wt. % ThO2, crystals of which have a characteristic sectoral zonation with respect to titanium and thorium contents. We have investigated the crystal structure of «ivanyukite-Th» and established theoretical modeling of Th4+ incorporation into various structural positions of ivanyukite. The most probable scheme includes cation exchange of extraframework cations onto Th, with partial removing of Ti from the titanosilicate framework.