Synthesis and properties of uranium sulfide cations. An evaluation of the stability of thiouranyl, {S═U═S}2+.

Atomic uranium cations, U(+) and U(2+), reacted with the facile sulfur-atom donor OCS to produce several monopositive and dipositive uranium sulfide species containing up to four sulfur atoms. Sequential abstraction of two sulfur atoms by U(2+) resulted in US2(2+); density functional theory computations indicate that the ground-state structure for this species is side-on η(2)-S2 triangular US2(2+), with the linear thiouranyl isomer, {S═U(VI)═S}(2+), some 171 kJ mol(-1) higher in energy. The result that the linear thiouranyl structure is a local minimum at a moderate energy suggests that it should be feasible to stabilize this moiety in molecular compounds.