A potassium sodium double salt of metavanadate, KNa(VO₃)₂

Abstract

Potassium sodium metavanadate, KNa(VO3)2, crystallizes with the pyroxene structure and is made up of VO4 tetrahedral chains, NaO6 octahedra and KO8 dodecahedra. The chains of corner-sharing VO4 tetrahedra are crosslinked through the NaO6 octahedra and KO8 dodecahedra to form a three-dimensional structure with the K+ and Na+ cations, which lie on twofold axes, situated in the void space. The coordination around the Na+ ion is close to normal octahedral, while the O atoms coordinated to the K+ ion are arranged approximately in a dodecahedral fashion.

Crystal structure of thorium metavanadate (Th(VO3)4)

“…The tetrahedral bond angles remain within 104 • to 113 • . These values are also in agreement with the typical tetrahedral vanadates in various metavanadates [17,6,[22][23][24][25][26]. Thorium atoms form eight coordinated polyhedra and can be written as ThO (4) The identical vanadium atom is repeated at every fifth atoms of the chain.…”

“…In the present compound as well as the earlier reported Np(VO 3 ) 4 , the total crystal structure is not related to the perovskite with respect to the VO 4 chain. Such vanadium chains are closely similar to most of the catena type vanadates [6][7][8][9]22] and pyroxene type silicates [7]. The presence of folded chains (spiral chains) and symmetrical absence of thorium atoms in the crystal structure is expected to affect several physical properties, namely expansion, compressibility, etc.…”

Retracted: Dual‐Ion Stabilized Layered Structure of OVO for Zero‐Strain Potassium Insertion and Extraction

“…The crystal structure was further confirmed by XRD results (Figure 1d ). The crystallinity of NaK(VO 3 ) 2 ‐V 2 O 5 has two Vanadium‐Based Oxides (NaK(VO 3 ) 2 : PDF#26‐1474 and V 2 O 5 : PDF#41‐1426) and is obviously lower than that in the literature, [ 13 ] which is related to the increased disorder of crystal structure caused by some vacancies, it can further accelerate the rapid transfer of electrons in the charging and discharging process due to the V 2 O 5 provide more space. X‐ray photoelectron spectroscopy (XPS) results confirmed that the electron cloud bias from electron‐rich —V═O‐ and —V—O—V‐ component to low binding energy field inducing the formation of built‐in electric field at the heterojunction interface (Figure 1e,f ), which may accelerate the charge transfer dynamics at the heterogeneous interface.…”