Using Phosphonates to Probe Structural Differences Between Transuranium Elements and Their Proposed Surrogates

Uncovering the Origin of Divergence in the CsM(CrO4)2 (M = La, Pr, Nd, Sm, Eu; Am) Family through Examination of the Chemical Bonding in a Molecular Cluster and by Band Structure Analysis

“…Examples of this include replacing Pu IV with Ce IV or Am III with Eu III . [20][21][22][23][24][25][26][27][28][29] These substitutions are often based on similarities between ionic radii. 20 However, the aforementioned changes in electronic structure and the increased involvement of frontier orbitals in the actinides creates dissimilarities between the 4f and 5f series that manifests in unexpected coordination chemistry, electronic properties, and reactivity.…”

“…For example, the reactivity and coordination environments of cerium and plutonium diverge in phosphonates, 23,25 carboxypyridinonates, 30,31 and hydroxypyridinonates. 21,[32][33][34] The enthalpy of complexation of Am III by softer donors ligands is notably stronger than it is for Eu III and can be exploited for separating Am III from lanthanides in used nuclear fuel recycling.…”

“…There are radiologic and reaction-scale challenges that are inherent to working with actinides that lie beyond uranium that often force the use of benign analogs for these elements. Examples of this include replacing Pu IV with Ce IV and Am III with Eu III . − These substitutions are often based on similarities between ionic radii . However, the aforementioned changes in electronic structure and the increased involvement of frontier orbitals in the actinides create dissimilarities between the 4f and 5f series that manifest in unexpected coordination chemistry, electronic properties, and reactivity.…”

“…However, the aforementioned changes in electronic structure and the increased involvement of frontier orbitals in the actinides create dissimilarities between the 4f and 5f series that manifest in unexpected coordination chemistry, electronic properties, and reactivity. For example, the reactivity and coordination environments of cerium and plutonium diverge in phosphonates, , carboxypyridinonates, , and hydroxypyridinonates. ,− The enthalpy of complexation of Am III by softer donors ligands is notably stronger than it is for Eu III and can be exploited for separating Am III from lanthanides in used nuclear fuel recycling. ,− Contracted M–L bonds have also been measured and calculated in M­[N­(EPR 2 ) 2 ] 3 complexes (M = U, Pu; E = S, Se, Te; R = Ph, i Pr, H) that are consistent with enhanced covalency in An–E bonds versus that found with lanthanides …”

From Yellow to Black: Dramatic Changes between Cerium(IV) and Plutonium(IV) Molybdates

“…In the tetravalent state, discrepancies have been shown between Ce(IV) and Pu(IV) as well as between early An(IV) and transuranic An(IV). [4][5][6][7][8][9][10][11][12][13][14] Exploration of this field is filled with opportunity as there are only a few systems that have systematically spanned the lanthanide and actinide series such as the aquo-triflates, phosphonates, and phosphites. [15][16][17][18][19][20][21][22][23][24][25] It is in this objective we have chosen to explore the rare earth molybdates.…”