A 70-Year-Old Mystery in Technetium Chemistry Explained by the New Technetium Polyoxometalate [H7 O3 ]4 [Tc20 O68 ] â
4H2 O.
Chemistry
; 27(54): 13624-13631, 2021 Sep 24.
Article
em En
| MEDLINE
| ID: mdl-34245056
ABSTRACT
[H7 O3 ]4 [Tc20 O68 ] â
4H2 O [1] was prepared from an aqueous Tc2 O7 solution concentrated over anhydrous H2 SO4 . [Tc20 O68 ]4- is the first polyanionic species to be reported for Tc. The unit cell contains one centrosymmetric [Tc20 O68 ]4- polyanion as well as hydronium ions and water molecules. The core of the structure consists of four Tc(V)O6 octahedra that form a square Tc4 O4 ring. The four Tc(V)O6 octahedra are decorated by sixteen Tc(VII)O4 tetrahedra. Calculations show the bonding within the Tc4 O4 ring to consist of a 3-center bond formed between each neighboring pair of Tc atoms and their bridging oxygen. Calculations also indicate that a strong dâd electronic transition at 513â
nm is the origin of the red color of [1]. The characterization of red HTcO4 solutions by X-ray absorption spectroscopy has complemented the description of this compound in aqueous solution. The formation mechanisms in solution, including the possible role of technetium's radioactivity in the formation of [1], are discussed.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Chemistry
Ano de publicação:
2021
Tipo de documento:
Article