Picomolar Traces of Americium(III) Introduce Drastic Changes in the Structural Chemistry of Terbium(III): A Break in the "Gadolinium Break"

Jan M Welch; Danny Müller; Christian Knoll; Martin Wilkovitsch; Gerald Giester; Johannes Ofner; Bernhard Lendl; Peter Weinberger; Georg Steinhauser

doi:10.1002/anie.201703971

Picomolar Traces of Americium(III) Introduce Drastic Changes in the Structural Chemistry of Terbium(III): A Break in the "Gadolinium Break"

Angew Chem Int Ed Engl. 2017 Oct 16;56(43):13264-13269. doi: 10.1002/anie.201703971. Epub 2017 Aug 31.

Authors

Jan M Welch¹, Danny Müller², Christian Knoll², Martin Wilkovitsch², Gerald Giester³, Johannes Ofner⁴, Bernhard Lendl⁴, Peter Weinberger², Georg Steinhauser⁵

Affiliations

¹ TU Wien, Atominstitut, Stadionallee 2, 1020, Vienna, Austria.
² TU Wien, Institute of Applied Synthetic Chemistry, Getreidemarkt 9/163-AC, 1060, Vienna, Austria.
³ University of Vienna, Institute of Mineralogy and Crystallography, Althanstrasse 14, 1090, Vienna, Austria.
⁴ TU Wien, Institute of Chemical Technologies and Analytics, Getreidemarkt 9/164, 1060, Vienna, Austria.
⁵ Leibniz Universität Hannover, Institute of Radioecology and Radiation Protection, Herrenhäuser Strasse 2, 30419, Hannover, Germany.

PMID: 28745419
DOI: 10.1002/anie.201703971

Abstract

The crystallization of terbium 5,5'-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H₂ O)₇ ZT]₂ ZT⋅10 H₂ O is isostructural to light lanthanide (Ce-Gd) 5,5'-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5'-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H₂ O)₈ ]₂ ZT₃ ⋅6 H₂ O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10⁸ -fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microcopy. In addition, the inclusion properties of terbium 5,5'-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed.

Keywords: actinides; energetic anions/ligands; gadolinium break; lanthanides; structural influence.