R3: High-pressure science and deep Earth’s material

[R3-09] Compressibility and blue-shifting OH groups of Mg(OH)F under high pressure

*Xuejing He¹, Hiroyuki Kagi¹, Kazuki Komatsu¹, Satoshi Nakano² (1. UTokyo, 2. NIMS)

Keywords:magnesium hydroxyfluoride, high pressure, diamond anvil cell, X-ray diffraction, infrared spectroscopy

In-situ high-pressure synchrotron XRD and FTIR experiments have been conducted up to ~20 GPa at room temperature using DACs, to investigate compressibility and spectroscopic properties of Mg(OH)F (Pnma, Z = 4). The P-V correlation is fitted by the 2nd-order Birch-Murnaghan Equation of State, yielding K₀ = 80(2) GPa, K₀' = 4.0 (fixed), and V₀ = 145.2(3) cubic anstrom. Positive pressure dependence of the O-H stretching mode frequencies indicates that the O-H...F hydrogen-bond does not strengthen under compression.