Over-Stoichiometry in Heavy Metal Oxides: The Case of Iono-Covalent Tantalum Trioxides.

Title Over-Stoichiometry in Heavy Metal Oxides: The Case of Iono-Covalent Tantalum Trioxides.
Authors Y.J. Lee; T. Lee; A. Soon
Journal Inorg Chem
DOI 10.1021/acs.inorgchem.8b00578

Oxides of tantalum (common examples including TaO, TaO, and TaO) are key oxide materials for modern electronic devices, such as dynamic random-access memory and field effect transistors. Of late, new forms of stable tantalum oxides have been proposed as two-dimensional nanosheet structures with a nonconventional stoichiometry of TaO via soft-chemical delamination of RbTaO. However, not much is known about the elusive nanosheet-structured TaO, unlike other closely related common trioxides of W and Mo. In this work, using first-principles density functional theory calculations, we have studied various TaO structures as inspired from previous theoretical and experimental studies and discuss their properties with respect to the more conventional oxide of tantalum, TaO. We have calculated their thermodynamics and lattice properties and have found a new stable-layered ?-TaO and its exfoliated monolayer phase (?'). By further analyzing their electronic structures, we discuss the mixed iono-covalent bonding characteristics in the TaO phases, challenging the conventional formal oxidation state model for metal oxides. Finally, we propose how these new TaO oxide materials may be potentially useful in photodevice applications.

Citation Y.J. Lee; T. Lee; A. Soon.Over-Stoichiometry in Heavy Metal Oxides: The Case of Iono-Covalent Tantalum Trioxides.. Inorg Chem. 2018;57(10):60576064. doi:10.1021/acs.inorgchem.8b00578

Related Elements


See more Tantalum products. Tantalum (atomic symbol: Ta, atomic number: 73) is a Block D, Group 5, Period 6 element with an atomic weight of 180.94788. Tantalum Bohr ModelThe number of electrons in each of tantalum's shells is [2, 8, 18, 32, 11, 2] and its electron configuration is [Xe] 4f14 5d3 6s2. The tantalum atom has a radius of 146 pm and a Van der Waals radius of 217 pm. High Purity (99.999%) Tantalum (Ta) MetalTantalum was first discovered by Anders G. Ekeberg in 1802 in Uppsala, Sweden however, it was not until 1844 when Heinrich Rose first recognized it as a distinct element. In its elemental form, tantalum has a grayish blue appearance. Tantalum is found in the minerals tantalite, microlite, wodginite, euxenite, and polycrase. Due to the close relation of tantalum to niobium in the periodic table, Tantalum's name originates from the Greek word Tantalos meaning Father of Niobe in Greek mythology.

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