R2: Crystal structure, crystal chemistry, physical properties of minerals, crystal growth and applied mineralogy

[R2-07] Structural Analysis of ilvaite: distribution of Fe²⁺, Fe³⁺ and Mn²⁺.

[Presentation award entry]

*Yutaro Inoue¹, Toru Kawamata², Takashi Mikouchi³, Kazumasa Sugiyama² (1. Eng. Tohoku Univ., 2. IMR Tohoku Univ., 3. The University Museum, The Univ. of Tokyo)

Keywords:ilvaite, Single-crystal X-ray diffraction, Anomalous X-ray Scattering

Anomalous X-ray scattering (AXS) measurements were performed on the ilvaite sample from Smolyan (CaFe²⁺₂Fe³⁺ Si₂O₇O(OH)), to determine the distribution of Mn, Fe²⁺ and Fe³⁺. Mn-AXS measurement revealed that Mn was selectively located at the Fe2 site and not at either of Fe11 and Fe12 sites. In addition, Fe-AXS measurement suggested that Fe²⁺ was randomly distributed in the Fe11 and Fe12 sites. The rather random distribution of Fe²⁺ among the Fe11 and Fe12 sites corresponds well with the lower σ value estimated by the averaged interatomic distances.