Possible Sites for Hydrogen in a New Hydrous Magnesium Silicate Phase G Synthesized at 22 GPa and 1050°C

Abstract

A single crystal ofphase G, Mg_{1. 24}Si_{1. 76}H_{2. 48}O₆was analized with synchrotron radiation. The structure ofphase G has close structural similarity to that ofstishovite, SiO₂. The valence sum ofthe O site is 1. 52, indicating the existenceofhydrogen bonding as anion chemistry for oxygen being OH_1/2. The possible sites for hydrogen are along the O-O edge of vacant tetrahedrabetween corners of MgO₆ octahedrawhich are separated by a distance of 2. 654 (6) Å.