Abstract
The title compound, sodium (sodium,manganese) triiron(II,III) tris[vana-date(V)], (Na0.70)(Na0.70,Mn0.30)(Fe(3+),Fe(2+))2Fe(2+)(VO4)3, was prepared by solid-state reactions. It crystallizes in an alluaudite-like structure, characterized by a partial cationic disorder. In the structure, four of the 12 sites in the asymmetric unit are located on special positions, three on a twofold rotation axis (Wyckoff position 4e) and one on an inversion centre (4b). Two sites on the twofold rotation axis are entirely filled by Fe(2+) and V(5+), whereas the third site has a partial occupancy of 70% by Na(+). The site on the inversion centre is occupied by Na(+) and Mn(2+) cations in a 0.7:0.3 ratio. The remaining Fe(2+) and Fe(3+) atoms are statistically distributed on a general position. The three-dimensional framework of this structure is made up of kinked chains of edge-sharing [FeO6] octa-hedra stacked parallel to [10-1]. These chains are held together by VO4 tetra-hedral groups, forming polyhedral sheets perpendicular to [010]. Within this framework, two types of channels extending along [001] are present. One is occupied by (Na(+)/Mn(2+)) while the second is partially occupied by Na(+). The mixed site containing (Na(+)/Mn(2+)) has an octa-hedral coordination sphere, while the Na(+) cations in the second channel are coordinated by eight O atoms.
Highlights
The title compound, sodium triiron(II,III) tris[vanadate(V)], (Na0.70)(Na0.70,Mn0.30)(Fe3+,Fe2+)2Fe2+(VO4)3, was prepared by solid-state reactions
Four of the 12 sites in the asymmetric unit are located on special positions, three on a twofold rotation axis (Wyckoff position 4e) and one on an inversion centre (4b)
Two sites on the twofold rotation axis are entirely filled by Fe2+ and V5+, whereas the third site has a partial occupancy of 70% by Na+
Summary
The synthesis and structural characterization of transition-metal-based functional materials adopting layered or channel structures has been the focus of much scientific work. Alluauditetype phosphates are of special interest as positive electrode materials in lithium and sodium batteries. Responding to the growing demand for this type of functional materials, we were able to prepare new alluaudite-type phosphates within pseudo-ternary A2O/MO/P2O5 or pseudoquaternary A2O/MO/Fe2O3/P2O5 systems by means of hydrothermal or solid-state reactions: AgMg3(HPO4)2PO4. M0 2O3/V2O5 system (A = monovalent cation, M = bivalent cation and M0 = trivalent cation) with approximate molar ratios of A:M:M0 :V = 2:2:1:3 and report here details of the preparation and structural characterization of the first sodiummanganese- and iron-based vanadate with an alluaudite-type structure, viz. A layer perpendicular to [010], resulting from the connection of chains via vertices of VO4 tetrahedra
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Acta crystallographica. Section E, Crystallographic communications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.