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Title: Synthesis and characterization of novel barium iron phosphates: Insight into new structure types tailored by hydrogen atoms

A significant gap in our knowledge of phosphate crystal chemistry is the lack of understanding of what controls the depolymerization of [PO{sub 4}] tetrahedra. A new route using phosphoric acid without any added water at 240 °C has been developed to synthesize two new compounds Ba{sub 2}Fe{sub 2}[H(PO{sub 3}OH){sub 2}][H(P{sub 2}O{sub 7}){sub 2}] and Ba{sub 2}Fe[H(P{sub 2}O{sub 7}){sub 2}], as well as a new polymorph β-BaFe{sub 2}(P{sub 2}O{sub 7}){sub 2} from annealing the former at ≥500 °C. Structural characterizations show that Ba{sub 2}Fe{sub 2}[H(PO{sub 3}OH){sub 2}][H(P{sub 2}O{sub 7}){sub 2}] features a novel 2D {sup 2}{sub ∞}([Fe{sub 2}[H(PO{sub 3}OH){sub 2}][H(P{sub 2}O{sub 7}){sub 2}]]{sup 4−}) layer structure containing both hydrogen-diphosphate [H(P{sub 2}O{sub 7}){sub 2}] and hydrogen-monophosphate [H(PO{sub 3}OH){sub 2}] groups, whereas Ba{sub 2}Fe[H(P{sub 2}O{sub 7}){sub 2}] and β-BaFe{sub 2}(P{sub 2}O{sub 7}){sub 2} possess an 1D chain structure and a 3D framework structure, respectively. These structures support a control of hydrogen on the depolymerization of [PO{sub 4}] groups and our work opens a new way for the synthesis of other novel phosphates using controlled water activities. - Graphical abstract: A new route of controlled water activities led to syntheses of three new compounds, indicating water plays a crucial role in the formation ofmore » novel phosphates. - Highlights: • A new mild thermal route for the synthesis of novel phosphates. • Water activities controlling the reaction: 2H{sub 3}PO{sub 4}↔H{sub 4}P{sub 2}O{sub 7}+H{sub 2}O. • Phosphate with mixed hydrogen-monophosphate and diphosphate groups. • H atoms in the structural backbone affect the depolymerization of PO{sub 4} groups.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Fujian Provincial Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, Fujian Province (China)
  2. Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK, Canada S7N 5E2 (Canada)
Publication Date:
OSTI Identifier:
22334163
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 212; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CONTROL; CRYSTAL STRUCTURE; CRYSTALS; DEPOLYMERIZATION; HYDROGEN; IRON PHOSPHATES; SYNTHESIS