title: Study of the structural, electronic, and magnetic properties of the barium-rich iron(IV) oxides, Ba(2)FeO(4) and Ba(3)FeO(5).
abstract: Crystals of Ba(2)FeO(4) and Ba(3)FeO(5), grown from a "self-sealing" KOH-Ba(OH)(2) flux, have been characterized by single-crystal X-ray diffraction, Mössbauer spectroscopy, and magnetic measurements. Ba(2)FeO(4) forms nonmerohedral twinned crystals with the monoclinic space group P2(1)/n, a = 6.034(2) A, b = 7.647(2) A, c = 10.162(3) A, beta = 92.931(6) degrees, and Z = 4. Ba(3)FeO(5) crystallizes in the orthorhombic space group Pnma, with a = 10.301(1) A, b = 8.151(1) A, c = 7.611(1) A, and Z = 4. While both compounds feature discrete FeO(4)(4-) tetrahedra, the anion found in Ba(2)FeO(4) has shorter Fe-O bonds and is significantly distorted relative to the Ba(3)FeO(5) anion. An iron valence of 4+ was confirmed by magnet susceptibility measurements and by the low-temperature isomer shifts of -0.152 and -0.142 mm/s relative to alpha-iron for Ba(2)FeO(4) and Ba(3)FeO(5), respectively.
authors.affiliation: Department of Chemistry, University of California-Berkeley, Berkeley, California 94720, USA.
authors.forename: James L
authors.initials: JL
authors.lastname: Delattre
authors.forename: Angelica M
authors.initials: AM
authors.lastname: Stacy
authors.forename: Victor G
authors.initials: VG
authors.lastname: Young
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Long
authors.forename: Raphaël
authors.initials: R
authors.lastname: Hermann
authors.forename: Fernande
authors.initials: F
authors.lastname: Grandjean