Compression behaviors of distorted rutile-type hydrous phases, MOOH (M = Ga, In, Cr) and CrOOD

Sano, Asami   ; Yagi, Takehiko*; Okada, Taku*; Goto, Hirotada*; Kikegawa, Takumi*

X-ray diffraction measurements of distorted rutile-type oxyhydroxides -GaOOH, InOOH, -CrOOH, and -CrOOD were taken at a maximum pressure of up to 35 GPa under quasi-hydrostatic conditions, at ambient temperature. Anomalies in the evolution of the relative lattice constants and the axial ratios of -GaOOH, InOOH, and -CrOOD suggest anisotropic stiffening along the a- and/or b-axes where the hydrogen bond is formed. The changes were observed at 15 GPa in -GaOOH and InOOH and at 4 GPa in -CrOOD. The pressures were higher in oxyhydroxides that have longer O...O distances of the hydrogen bond at ambient pressure. In contrast, such stiffening behavior was not observed in CrOOH, which has a significant short O...O distance and strong hydrogen bond. The stiffening behaviors observed in the present study can be attributed to the symmetrization of the hydrogen bonds in oxyhydroxides, as was previously found in -AlOOH(D).