Although the trivalent actinides are similar to the lanthanide series in terms of chemistry and bonding, their structures and properties can diverge significantly. Here, the authors report a series of...

Complexes containing hydroxide, water and dinitrogen ligands detected as researchers probe chemistry on the edge of the actinide series

This review outlines the structure and chemistry of divalent lanthanides and actinides in small molecule systems, focusing on the less accessible diva…

This theoretical study investigates the UV–vis absorption properties of U4+-containing aqueous solutions and their relationship with the nature of aqua-complexes present at varying acidic levels. High...

An example of a 249Bk3+ phosphine oxide complex has been prepared to examine and quantify the effects of the inverse trans-influence (ITI) on a late actinide complex. This has been accomplished through a comparison of cis and trans Bk-ligand bonds in the meridional berkelium(III) complex, BkBr3(OPCy3)3 (OPCy3 = tricyclohexylphosphine oxide). A detailed bond metric analysis was completed that includes the shortest published distance for a Bk3+–O bond, attributed to the smaller coordination number of Bk3+ of six in mer-BkBr3(OPCy3)3. ITI calculations of the trans Bk3+–O bond provide an ITI value (98.5(2)%) comparable to that of mer-AmBr3(OPCy3)3 (98.2(2)%) and indicate a small 5f orbital contribution to bonding. This effect is discussed in the context of the isomorphous lanthanide(III) series where the ITI is calculated to be higher for mer-BkBr3(OPCy3)3 than in most Ln3+ analogues.

A trivalent plutonium–pyrazinyl–tetrazolate complex Na2[Pu(Hdtp)(dtp)2(H2O)4]·9H2O (Pu_dtp, H2dtp = 2,3-di-1H-tetrazol-5-ylpyrazine) was synthesized through metathesis reaction of plutonium bromide an...

Nature Chemistry - The most common oxidation state for lanthanide elements is +3, and, beyond cerium, examples of these elements exhibiting higher oxidation states remain scarce. Now, a molecular...

Synthesis could help chemists better understand bonding

Diethylenetriaminepentaacetic acid (DTPA) is a frequently used chelator in the nuclear and medical industries, especially for the complexation of trivalent actinides. However, structural data on these complexes in the solid-state have long remained elusive. Herein, a detailed structural analysis of the presented crystal structures of [C(NH2)3]4[Nd(DTPA)]2·nH2O and [C(NH2)3]4[Am(DTPA)]2·nH2O, where [C(NH2)3]+ is guanidinium, details the subtle differences in the Lewis acidity between a lanthanide/actinide pair of similar ionic sizes. Contractions in nitrogen–metal bond lengths between neodymium(III) and americium(III) were observed, while the metal–oxygen bonds remained relatively consistent, highlighting the marginal favorability for actinide complexation over the lanthanides with moderately soft N-donors. Spectroscopic analysis shows significant splitting of many transitions and relatively strong electronic interactions with traditionally low-intensity transitions in the americium complex, as is demonstrated in the 7F0→7F5 transitions. Pressure-induced spectroscopic analysis showed surprisingly little effect on the americium complex, with 5f→5f transitions either not shifting or marginally shifting from 2 to 3 nm at 11.93 ± 0.06 GPa─atypical of a soft, N-donor americium complex under pressure. Large voids occupied by water molecules in between the complexes within the crystal structure may be responsible for the lack of pressure response in the 5f→5f transitions.

The isotope is critical for understanding Earth’s origins. An accurate half-life is key—and researchers may have finally measured it