High pressure neutron diffraction studies using the Paris-Edinburgh cell

TL;DR: In this paper, angle-dispersive x-ray diffraction using an imaging plate was used to investigate the high-pressure behavior of tin dioxide compounds at pressures up to 49 GPa.

TL;DR: Cubic Pa3-type RuO2 was prepared from the ambient pressure, rutile-structured phase at 20 GPa and 1100 °C in a multianvil device.

TL;DR: Wilding, M. C., Benmore, C. J. as mentioned in this paper, Structure and Glasses and Melts. review in Mineralogy and Geochemistry, 63 (1), 275-311 RAE2008

TL;DR: The high pressure form with a more silica-poor glass (Mg(2)SiO(4)) that represents the approach to a more dense, void-free and topologically ordered structure is compared and the degree of continuous connectivity of Si-O bonds increases via a collapse of interstices.

TL;DR: Boron-rich molecules and solids hold a special place within chemistry as mentioned in this paper and are very stable refractory materials with melting temperatures up to 2400°C, a thousand degrees higher than silicon's.

Abstract: The structures of deuterated ices VI, VII, and VIII have been studied under their conditions of stability by neutron powder diffraction. The mode of ordering of (tetragonal) ice VIII is clearly established, and no evidence is found of partial ordering as the temperature is raised. Ice VII is accurately cubic with D2O molecules disordered around their center of mass; there is no evidence of partial ordering at any temperature. The water molecule geometry is normal in both phases, and the hydrogen‐bonded first neighbor in ice VIII is confirmed to be more distant than the first nonbonded neighbor. The transition temperature between the two phases occurs at 263±2 K, some 11 K lower than expected. Hydrogen bond lengths in both phases are equal at the transition. Although the ice VI data are not as good, we can see no evidence of the antiferroelectric ordering proposed by Kamb from work on recovered samples. Our results are consistent with thermodynamic measurements indicating disorder in ice VI at 193 K. We co...

TL;DR: In this paper, the main topics are electronic structure, electronic and optical properties, superconductivity, crystal structure, magnetic properties, vibrational properties, thermal and elastic properties; phase diagrams; materials; preparation; mechanical properties; and applications.

TL;DR: High-pressure neutron diffraction studies of boron carbide show that the icosahedral structural units are 23(4)% more compressible than the structure between them, showing the effect of the structural compression on the electrical resistivity to be more complex than present, semiquantitative models suggest.