title: Investigation of reactivity and structure formation in a K-Te-U oxo-system under high-temperature/high-pressure conditions.
abstract: The high-temperature/high-pressure treatment of the K-Te-U oxo-family at 1100 °C and 3.5 GPa results in the crystallization of a series of novel uranyl tellurium compounds, K2[(UO2)3(TeIVO3)4], K2[(UO2)TeO14], α-K2[(UO2)TeVIO5] and β-K2[(UO2)TeVIO5]. In contrast to most of the reported uranyl compounds which are favorable in layered structures, we found that under extreme conditions, the potassium uranyl oxo-tellurium compounds preferably crystallized in three-dimensional (3D) framework structures with complex topologies. Anion topology analysis indicates that the 3D uranyl tellurite anionic framework observed in K2[(UO2)3(TeIVO3)4] is attributable to the additional linkages of TeO3polyhedra connecting with TeO4disphenoids from the neighboring U-Te layers. The structure of K2[(UO2)TeO14] can be described based on [UTe6O26]22-clusters, where six TeO5polyhedra enclose a hexagonal cavity in which a UO8polyhedron is located. The [UTe6O26]22-clusters are further linked by TeO5square pyramids to form the 3D network. Similar to uranyl tellurates, both α-K2[(UO2)TeVIO5] and β-K2[(UO2)TeVIO5] contain TeO6octahedra which share a common face to form a dimeric Te2O10unit. However, in α-K2[(UO2)TeVIO5], these Te2O10units connect with UO6tetragonal bipyramids to form a 3D structural framework, while in β-K2[(UO2)TeVIO5], the same Te2O10dimers are observed to link with UO7pentagonal bipyramids, forming 2D layers. Raman measurements were carried out and the vibration bands related to TeIV-O, TeVI-O and UVI-O bonds are discussed.
authors.affiliation: Institute for Energy and Climate Research (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany. e.alekseev@fz-juelich.de and Institut für Kristallographie, RWTH Aachen University, 52066 Aachen, Germany.
authors.forename: Bin
authors.initials: B
authors.lastname: Xiao
authors.affiliation: Institute for Energy and Climate Research (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany. e.alekseev@fz-juelich.de.
authors.forename: Philip
authors.initials: P
authors.lastname: Kegler
authors.affiliation: Institute for Energy and Climate Research (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany. e.alekseev@fz-juelich.de.
authors.forename: Dirk
authors.initials: D
authors.lastname: Bosbach
authors.affiliation: Institute for Energy and Climate Research (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany. e.alekseev@fz-juelich.de and Institut für Kristallographie, RWTH Aachen University, 52066 Aachen, Germany.
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Alekseev