Effects of Te(IV) Oxo-Anion Incorporation into Thorium Molybdates and Tungstates

The exploration of phase formation
in the Th–Mo/W–Te systems has resulted in four mixed
oxo-anion compounds from high-temperature solid-state reactions: ThWTe2O9, Th­(WO4)­(TeO3), ThMoTe2O9, and Th2(MoO4)­(TeO3)3. All four compounds contain edge-sharing thorium
polyhedra linked by MoO4/WO6 and different tellurium
oxo-groups to form three-dimensional frameworks. In ThWTe2O9, each helical Th based chain is connected by four tungstotellurite
clusters resulting in a building fragment which has a cross-section
of four-leafed clovers. The structure of Th­(WO4)­(TeO3) exhibits a multilayer-sandwich framework composed of thorium
tellurite layers with tungsten chains in between. In the case of the
molybdate family, ThMoTe2O9 and Th2(MoO4)­(TeO3)3 are built from puckered
Th–Te sheets which are further interconnected by MoO4 tetrahedral linkers. The DSC-TG technique was performed to gain
insight into the thermal behavior of the synthesized compounds. Raman
spectra of as-prepared phases were obtained and analyzed for signature
peaks.