Study of interaction between coprecipitated hydroxides of rare earths and titanium

Interaction of mutually precipitated hydroxides of titanium and rare earth elements obtained from water-methanol solutions has been studied. It has been shown that chemical interaction between Ti and r.e.e. begins at the moment of precipitation and the products of interaction are hydroxocomplexes of the composition Ln2[TiO2(OH)2]3nH2O. The intermediate compounds of the composition Lasub(2/3)TiO3 have been found in the temperature range 400-800 deg C when heating the hydroxocomplexes. Lanthanum metatitanate crystallizes as perovskite. The parameters of the rhombic elementary cell of Lasub(2/3)TiO3 are: a=4.06, b=4.11, c=8.00A, rhosub(exp)=4.67g/cm3, rhosub(calc)=4.69g/cm3. The number (Z) of the formula units Lasub(2/3)TiO3 in the elementary cell is 2. At 800 deg C metatitanates of r.e.e. decompose with the formation of dititanates of the composition Ln2Ti2O7. Ageing of mutually precipitated hydroxides of titanium and rare earth elements leads to destruction of hydroxocomplexes