ChemInform Abstract: Stabilization of Ca1-δFe2-xMnxO4 (0.44 ≤ x ≤ 2) with CaFe2O4-Type Structure and Ca2+ Defects in One-Dimensional (1D) Channels.

✍ Scribed by Tao Yang; Mark Croft; Alexander Ignatov; Israel Nowik; Rihong Cong; Martha Greenblatt

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 26 KB
• Volume: 42
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.201102002

✦ Synopsis

Stabilization of Ca 1-δ Fe 2-x Mn x O 4 (0.44 ≤ x ≤ 2) with CaFe 2 O 4 -Type Structure and Ca 2+ Defects in One-Dimensional (1D) Channels. -Solid solutions Ca1-δFe2-xMnxO4 (0.45 ≤ x ≤ 2) are synthesized from mixtures of CaCO3, Fe2O3, and Mn2O3 using CaCl2 as a flux (alumina crucible, 850 °C, 24 h). The products are characterized by powder XRD, XAS, and Moessbauer spectroscopy. All the compounds crystallize with the CaFe 2 O 4 -type structure in the space group Pnma. The stabilization of the CaFe2O4-type structure, even at high values of x, is due to the existence of non-Jahn-Teller active Mn 4+ (and Fe 3+ ), which is compensated by the formation of Ca 2+ deficiencies in the one-dimensional channels of Ca1-δFe2-xMnxO4 during the flux synthesis. All the compounds exhibit antiferromagnetic long-range ordering at low temperature. The Ca 2+ defects in the one-dimensional channels and Li + exchange for Ca 2+ in Ca1-δFe2-xMnxO4 suggest potential as a cathode material for lithium ion batteries.