X-ray Rietveld and 57Fe M^|^ouml;ssbauer study of babingtonite from Kouragahana, Shimane Peninsula, Japan

Abstract

Babingtonite from Kouragahana, Shimane Peninsula, Japan, was investigated using electron microprobe, X -ray Rietveld, and 57 Fe Mössbauer spectral analyses to characterize its chemical compositions, crystal structure, oxidation state of Fe, and distribution of Fe between two crystallographically independent octahedral Fe1 and Fe2 sites.The Kouragahana babingtonite occurs as single parallelohedrons with {100}, {001}, {001}, {111}, {1 82(2)

The Role of Scandium Substitution in Babingtonite Group Minerals

“…(θ i : O-M-O angle) [25]. Based on the published studies of babingtonite and manganbabingtonite [7][8][9][10], divalent cations, such as Mn 2+ and Mg, are assigned to M1, and small Al 3+ ions to M2, and the Fe ions are added until both M1 and M2 are full. Moreover, the previous 57 Fe Mössbauer studies, cited above, repeatedly resulted in the exclusive occupancy of ferrous and ferric ions at M1 and M2, respectively.…”

“…An undulating chain is built by five SiO 4 tetrahedra [6]. Ferrous and ferric iron is separated onto M1 and M2, respectively, based on the results of 57 Fe Mössbauer studies of babingtonite [1,[7][8][9][10]. The divalent Mn 2+ and Mg 2+ ions occupy the larger M1O 6 octahedra whereas the Al 3+ ions locate at the smaller M2O 6 octahedra [11].…”

Determination of the electric field gradient tensor of Fe³⁺ in the <i>M</i>1 site of aegirine by single crystal Mössbauer spectroscopy

“…In Mössbauer spectra of powder samples showing quadrupole splitting, two strongly overlapping doublets are commonly fitted by constraining the peak widths and intensities of the component peaks in a doublet to be equal (Bancroft et al, 1968;and others), although some minerals such as babingtonite (Akasaka et al, 2013) and siderite (Gol'Danskiĭ et al, 1968) show an asymmetry of quadrupole splitting components in their Mössbauer spectra. However, in single crystal Mössbauer spectra obtained from thin sections, the intensities of the component peaks of a quadrupole doublet are asymmetric and vary depending on the angle between the direction of incident γ-rays and the crystallographic orientation of the thin section.…”