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

[R2-11] Syntheses and single crystal structure analyses of Ir₂S₃ kashinite and Rh₂S₃ bowieite

*Akira YOSHIASA¹, Makoto Tokuda¹, Ginga Kitahara¹, Satoko Ishimaru¹, Akihiko Nakatsuka², Kazumasa Sugiyama³ (1. Kumamoto University, 2. Yamaguchi University, 3. Tohoku University)

Keywords:Ir2S3 kashinite, Rh2S3 bowieite, single crystal diffraction, Debye temperature,, Mantle constituent mineral

The crystal structures of Ir₂S₃ [space group Pbcn, a = 8.4728(3), b = 6.01563(18), c = 6.1537(2) Å] and Rh₂S₃ [space group Pbcn, a = 8.4672(3), b = 5.98537(18), c = 6.13921(19) Å] were determined by single-crystal X-ray diffraction analysis and refined to yield R1 values of 0.0174 and 0.0176 for 1092 and 1025 unique reflections, respectively. These compounds have a unique sesquisulfide structure in which pairs of face-sharing octahedra are linked to a three-dimensional structure by further edge- and vertex-sharing. The bulk Debye temperature for Rh₂S₃ bowieite (533K) was lower than that for Ir₂S₃ kashinite (576 K), which crystallizes in the early sequences of mineral crystallization differentiation from the primitive magma in Earth’s mantle.