Insights into Structural Diversity and Morphotropic Evolution in ATh(WO) (A=Li, Na, K, Rb and Cs) Family.

A series of four new thorium tungstates, ATh(WO) (A=Li, K, Rb, Cs), were synthesized using high-temperature solid-state method. Structural studies of the materials reveal distinct structural changes with underlying similarities influenced by the nature of A-site cations. LiTh(WO) exhibits a two-dimensional corrugated sheet structure stabilized by Li cations, crystallizing in P space group.

U(V) Stabilization via Aliovalent Incorporation of Ln(III) into Oxo-salt Framework.

Pentavalent uranium compounds are key components of uranium's redox chemistry and play important roles in environmental transport. Despite this, well-characterized U(V) compounds are scarce primarily because of their instability with respect to disproportionation to U(IV) and U(VI). In this work, we provide an alternate route to incorporation of U(V) into a crystalline lattice where different oxidation states of uranium can be stabilized through the incorporation of secondary cations with different sizes and charges.

Ultrafiltration separation of Am(VI)-polyoxometalate from lanthanides.

Partitioning of americium from lanthanides (Ln) present in used nuclear fuel plays a key role in the sustainable development of nuclear energy. This task is extremely challenging because thermodynamically stable Am(III) and Ln(III) ions have nearly identical ionic radii and coordination chemistry. Oxidization of Am(III) to Am(VI) produces AmO ions distinct with Ln(III) ions, which has the potential to facilitate separations in principle.

Understanding of the structural chemistry in the uranium oxo-tellurium system under HT/HP conditions.

The study of phase formation in the U-Te-O systems with mono and divalent cations under high-temperature high-pressure (HT/HP) conditions has resulted in four new inorganic compounds: K [(UO) (TeO)], Mg [(UO) (TeO)], Sr [(UO) (TeO)] and Sr [(UO) (TeO)]. Tellurium occurs as Te, Te, and Te in these phases which demonstrate the high chemical flexibility of the system. Uranium VI) adopts a variety of coordinations, namely, UO in K [(UO) (TeO), UO in Mg [(UO) (TeO)] and Sr [(UO) (TeO)], and UO in Sr [(UO) (TeO)].

Understanding the role of flux, pressure and temperature on polymorphism in ThBO.

A novel polymorph of ThBO, denoted as β-ThBO, was synthesised under high-temperature high-pressure (HT/HP) conditions. single crystal X-ray diffraction measurements, β-ThBO was found to form a three-dimensional (3D) framework structure where thorium atoms are ten-fold oxygen coordinated forming tetra-capped trigonal prisms. The only other known polymorph of ThBO, denoted α, synthesised herein using a known borax, BO-NaBO, high temperature solid method, was found to transform to the β polymorph when exposed to conditions of 4 GPa and ∼900 °C.