The striking feature of X-ray diffraction pattern vitreous silica is that the center its intense but broad ring located at nearly same position as strongest β-cristobalite. Two fundamentally different explanations to patterns were appeared about 90 years ago, one based on smallest crystals β-cristobalite and other non-crystalline continuous random network. This work briefly outlines facts suppo...

Large structural modifications in v-SiO2 are found to be induced by ‘‘thermal poling,’’ a treatment which makes the glass act as a frequency doubler of an impinging infrared light. The electron diffraction patterns of poled silica plates reveal the presence of a large amount ~of order 10%! of crystallites showing patterns consistent with partial crystallization of the glassy matrix into the cri...

Single crystals can commonly have negative Poisson's ratio in a few directions; however more generalised auxeticity is rarer. We propose a typology to distinguish auxetic materials. We characterise numerous single crystals and demonstrate that partial auxeticity occurs for around 37%. We find average auxeticity to be limited to α-cristobalite and no example of complete auxeticity. We simulate t...

We present a molecular dynamics simulation study of the structure and dynamics of water confined between silica surfaces using beta-cristobalite as a model template. We scale the surface Coulombic charges by means of a dimensionless number, k, ranging from 0 to 1, and thereby we can model systems ranging from hydrophobic apolar to hydrophilic, respectively. Both rotational and translational dyn...

Abstract Bitumen concrete construction and technical properties improvement when used as refuse finely-fragmented layer inorganic material formed in production of ceramic granite, material, is conditioned by its phase composition structure. The set physicochemical studies has established that the high physical granite are associated with microstructure, which presents glassceramic composite con...

Abstract We investigated the phase relations of SiO 2 -MgO-TiO system in air at 1500°C using high-temperature isothermal equilibration/quenching technique, followed by x-ray diffraction measurements and direct analysis scanning electron microscopy coupled with energy dispersive spectrometry. One single liquid domain, five two-phase domains (liquid-TiO , liquid-cristobalite, liquid-MgO·SiO liqui...

A new clathrate [K(H(2)O)(n)][CuZn(CN)(4)] has been synthesized and its host structure has been determined by the single-crystal X-ray diffraction method. It has a [CuZn(CN)(4)](-) tridymite-like 3D framework host, formed with tetrahedral Cu(I) and Zn(II) ions and cyanide bridges and includes water molecules as guests, together with K(+). This tridymite-like structure is the first structural va...