Nitrogen-Rich Compounds of the Lanthanoids: The 5,5′-Azobis[1H-tetrazol-1-ides] of some Yttric Earths (Tb, Dy, Ho, Er, Tm, Yb, and Lu)

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

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.

Poly[μ-(5,5'-diazenediylditetra-zolido)-dicaesium]

The asymmetric unit of the title compound, [Cs(2)(C(2)N(10))](n), comprises a Cs(+) cation, and one-half of a 5,5'-diazenediylditetra-zolide anion. The Cs(+) cation is six-coordinated by N atoms from six 5,5'-diazenediylditetra-zolide ligands. Each 5,5'-diazenediylditetra-zolide ligand is surrounded by 12 Cs(+) cations, coordinating through ten N atoms. The Cs(+) cations are arranged in a chain along the a-axis direction with a Cs⋯Cs separation of 4.4393 (10) Å. Such coordination leads to the formation of the three-dimensional framework.