K(Th_0.75Sr_0.25)₂Se₆: Structural Change Resulting from the Disorder of Differently Charged Cations

Abstract

Single crystals of K(ThSr)Se were obtained by a standard solid-state chemistry route at 1173 K. This compound does not belong to the AAnQ family (A = K, Rb, Cs, or Tl; An = Th, U, or Np; Q = S, Se, or Te) that possesses infinite Q-Q-Q chains and where a charge distribution of A, 2 × An, 2 × Q, 2 × (Q) has been proposed and hence a charge of -1.25 on Q of the "dichalcogenide". Rather in K(ThSr)Se, where the Th and Sr cations randomly occupy the same site, incorporation of these differently charged cations breaks the infinite Se-Se-Se chains into a structure that has typical Se pairs.

Targeted Synthesis of Uranium(IV) Thiosilicates

“…Numerous uranium chalcogenide compounds exhibiting complex structures, promising magnetic and electronic properties, and rare oxidation states − have been obtained from sulfide, halide, and other fluxes. − Driven by interest in the magnetic properties of uranium­(IV) compounds that offer a convenient probe for the magnetic behavior of 5f electrons, we have applied the iodide flux crystal growth approach to uranium­(IV) thiophosphates and obtained a new family of compounds with complex topologies . Extending this approach to new families of uranium compounds, we performed several syntheses involving silicon sulfide in an attempt to increase the content of positively charged countercations and extend the uranium thioanion framework by replacing PS 4 3– anions with SiS 4 4– .…”