Thorium

Solution Thermodynamic Stability of Complexes Formed with the Octadentate Hydroxypyridinonate Ligand 3,4,3-LI(1,2-HOPO): A Critical Feature for Efficient Chelation of Lanthanide(IV) and Actinide(IV) Ions

“…Prior to this work, 3 competition titrations against DTPA [log β 110 = 28.7 for Th(IV)] 7 and oxalic acid [log β 110 = 9.8, log β 120 = 17.5, log β 130 = 25.7, log β 140 = 29.6, for Th(IV)], 20 or simulations using competing ligands such as citric acid [log β 110 = 14.1, log β 120 = 24.3, log β 130 = 28.0 for Th(IV)] 20 or catechol [log β 110 = 18.1, log β 120 = 34.9 for Th(IV)] 7 failed to displace 3,4,3-LI(1,2-HOPO) from its complex with Th(IV). From these attempts, the stability constant of the [Th(IV)(3,4,3-LI(1,2-HOPO))] complex was evaluated to be higher than log β 110 38.5, making all known available ligands weaker than 3,4,3-LI(1,2-HOPO), and thereby making usual ligand-competition titrations ineffective to determine the formation constant of such a stable complex.…”

Oleum and Sulfuric Acid as Reaction Media: The Actinide Examples UO2(S2O7)‐lt (low temperature), UO2(S2O7)‐ht (high temperature), UO2(HSO4)2, An(SO4)2 (An = Th, U), Th4(HSO4)2(SO4)7 and Th(HSO4)2(SO4)

“…Cs 4 [Pt 12 O 8 (SO 4 ) 12 ] could be obtained. [2,3] Furthermore, sulfuric acid has the remarkable potential to stabilise metals in uncommon oxidation states.…”

“…Furthermore, sulfuric acid as well as sulfates of these elements play an important role in the processing of monazite ores when it comes to the order of isolating the rare-earth elements in this mineral. [12] The first step is the digestion of the respective ores in concentrated sulfuric acid, whereupon the rare-earth elements as well as uranium and thorium dissolve. The separation of the desired rare-earth metals from thorium and uranium is maintained by selective hydrolysation steps and precipitation processes.…”

Synthesis, structure, and reactivity of crystalline molecular complexes of the {[C5H3(SiMe3)2]3Th}1− anion containing thorium in the formal +2 oxidation state

“…7 l Gas-phase studies of Th 2+ indicate a ground state of 5f 1 6d 1 , but the 6d 2 configuration is just 63 cm –1 higher and the 5f 1 7s 1 is 2527 cm –1 higher than the ground state. 15 For (Cp 3 Th) 1– the triplet 5f 1 6d 1 state is computed to be 9–14 kcal mol –1 higher in energy than the singlet 6d 2 ground state.…”