ChemInform Abstract: STRUCTURE OF β‐SODIUM FERRATE (β‐NAFE2O3)

Abstract

β‐NaFezOa kristallisiert hexagonal‐rhomboedrisch in der Raumgruppe P 321, P3ml oder P3ml.

Synthesis of mixed-valent α- and β-NaFe2O3 polymorphs under controlled partial oxygen pressure

“…Preparation methods and crystal structures of a-and bNaFe 2 O 3 were reported in the 1970s by El Balkhi et al [14,15]. For the synthesis of the NaFe 2 O 3 polymorphs, mixtures of NaFeO 2 , Fe 2 O 3 and Fe were sealed in ampoules and annealed at 1000 1C for 48 h. The a and b phases were originally prepared in sealed steel and Cu ampoules, respectively.…”

“…The only known example is b-NaFe 2 O 3 ; its crystal structure consists of double rock-salt layers of octahedrally coordinated iron (Fe 2 O 3 blocks) separated by Na ions (Fig. 1) [14][15][16][17]. Generally speaking, 3d metal compounds with b-NaFe 2 O 3 structures are expected to demonstrate different properties than their a-NaFeO 2 type counterparts due to the difference in M oxidation states as well as in the dimensionality of the 3d metal -oxygen blocks.…”

“…literature[15]. a-NaFe 2 O 3 and b-NaFe 2 O 3 samples used in SPXD experiments were prepared at 2.3 Â 10 À 31 and 7.5 Â 10 À 16 atm pO 2 , respectively.…”