posted on 2017-02-13, 17:53authored byBin Xiao, Philip Kegler, Dirk Bosbach, Evgeny V. Alekseev
Through the use of
a high-temperature/high-pressure synthesis method, four thorium oxo-tellurium
compounds with different tellurium valence states were isolated. The
novel inorganic phases illustrate the intrinsic complexity of the
actinide tellurium chemistry under extreme conditions of pressure
and temperature. Th2Te3O11 is the
first instance of a mixed-valent oxo-tellurium
compound, and at the same time, Te exhibits three different coordination
environments (TeIVO3, TeIVO4, and TeVIO6) within a single structure. These
three types of Te polyhedra are further fused together, resulting
in a [Te3O11]8– fragment.
Na4Th2(TeVI3O15) and K2Th(TeVIO4)3 are the first alkaline thorium tellurates described in the
literature. Both compounds are constructed from ThO9 tricapped
trigonal prisms and TeVIO6 octahedra. Na4Th2(TeVI3O15) is a three-dimensional framework based on Th2O15 and Te2O10 dimers, while K2Th(TeVIO4)3 contains tungsten oxide bronze
like Te layers linked by ThO9 polyhedra. The structure
of β-Th(TeIVO3)(SO4) is built from infinite thorium chains cross-linked by TeIVO32– and SO42– anions. Close structural analysis suggests that β-Th(TeIVO3)(SO4) is highly related to
the structure of α-Th(SeO4)2. Additionally,
the Raman spectra are recorded and the characteristic peaks are assigned
based on a comparison of reported tellurites or tellurates.