Crystal structures of the low-temperature quartz-type phases of SiO₂ and GeO₂ at elevated pressure

Abstract

Quartz / Si0 2 / GeO z / Pressure / Crystal chemistry / Crystal structuresAbstract Lattice parameters and crystal structures of the low-temperature quartz-type ('low-quartz') forms (space group P3i21) of Si0 2 and Ge0 2 were refined from single-crystal X-ray diffraction data under hydrostatic pressures up to 10.2 GPa for Si0 2 and 5.57 GPa for Ge0 2 . R W (F) values range from 2 to 5%.

A Neutron Diffraction Study of the Thermal Stability of the α-Quartz-Type Structure in Germanium Dioxide

“…1 and 2 and Tables 1-5) are in very good agreement with previous single-crystal X-ray diffraction studies on small crystals (5,14). In fact, the intertetrahedral Ge-O-Ge bridging angle, y; and the tilt angle, d; which are very sensitive to the fractional atomic coordinates agree remarkably well.…”

“…In both cases, the space group is P3 1 21 (or P3 2 21) with Z ¼ 3: The piezoelectric coupling coefficient of these materials was found to increase linearly as a function of structural distortion with respect to b-quartz structure type. This distortion can be described in terms of the intertetrahedral A-O-B bridging angle, y; or the tilt angle with respect to the b-quartz structure type, d (note for b-quartz y ¼ 1541; d ¼ 01)U The most distorted structures found among a-quartz homeotypes (3,5) are those of GeO 2 (y ¼ 130:01; d ¼ 26:61) and GaAsO 4 (y ¼ 129:61; d ¼ 26:91). Based on structureproperty relationships, these compounds should exhibit the highest piezoelectric coupling coefficients for a-quartztype materials.…”

Investigation of the irreversible reaction mechanism and the reactive trigger on SiO anode material for lithium-ion battery

“…24) Figure 8 shows the possible empty sites in crystalline SiO 2 , which belong to the quartz structure with P3121 space group. These were calculated in Si 3 O 6 basic units using the find empty space tool of MedeA.…”

Evidence for residual elastic strain in deformed natural quartz

“…A scan is performed in a few hours, data processing takes considerably longer. In each Laue image, multiple spots were indexed using reference values for the quartz unit cell (a = 4.921 Å, c = 5.4163 Å, Glinnemann et al 1992). The misfit between the indexed patterns and the reference patterns are interpreted as residual elastic strain.…”