Bis(guanidinium) cyananilate

The asymmetric unit of the title compound, 2CH6N3 +·C8N2O4 2−, contains one half of a centrosymmetric 2,5-di­cyano-3,6-dioxocyclo­hexa-1,4-diene-1,4-diolate (cyananil­ate) anion and one guanidinium cation, which are connected by N—H⋯O and N—H⋯N hydrogen bonds into a three-dimensional network

Scanning Electron Microscope Examination of Quartz Surface Textures from Kaolinized Granitic Rocks

Observation of surfaces of quartz in kaolinized granitic rocks by scanning electron microscopy was applied to provide information on the environmental conditions of kaolinization. Comparing with the quartz grain surfaces from kaolinite and halloysite specimens each other, quartz crystals from kaolinite specimens show extremely rough surfaces caused by deep dissolution pits, while the surfaces from halloysite are relatively smooth surfaces. Quartz surfaces in hydrothermal kaolinized granitic rocks are extremely rougher than those in weathered granitic rocks

Selective occupancy of methane by cage symmetry in TBAB ionic clathrate hydrate.

Methane trapped in the two distinct dodecahedral cages of the ionic clathrate hydrate of TBAB was studied by single crystal XRD and MD simulation

C-Methyl­calix[4]resorcinarene–1,4-bis­(pyridin-3-yl)-2,3-diaza-1,3-butadiene (1/2)

In the title compound, 2C12H10N4·C32H32O8, the calixarene adopts a rctt conformation with dihedral angles of 138.40 (1) and 9.10 (1)° between the opposite rings. The dihedral angles between the rings of the pyridine derivative are 8.80 (1) and 9.20 (1)°. In the crystal, adjacent C-methylcalix[4]resorcinarene molecules are connected into columns parallel to [010] by O—H⋯O hydrogen bonds. O—H⋯N hydrogen bonds between the axial phenoxyl groups and bipyridine molecules link the columns into sheets parallel to (011), which are connected by O—H⋯N hydrogen bonds. Further O—H⋯N hydrogen bonds link the bipyridine and C-methylcalix[4]resorcinarene molecules, giving rise to a three-dimensional network

Switchable mesomeric betaines derived from pyridinium-phenolates and bis(thienyl)ethane

Syntheses of push–pull substituted non-symmetric bis(thienyl)ethenes (BTEs) possessing a central perfluorocyclopentene core are described. The substituent effects of anisole, phenole, and phenolate as well as pyridine, pyridinium, and N-methylpyridinium substituents, joined through their 3- or 4-positions to the central BTE core, respectively, cover the range from very strongly electron-donating [σ(4-phenolate)=−1.00] to extremely strongly electron-withdrawing [σ(pyridinium-4-yl)=+2.57] in the title mesomeric betaines. The different isomers possessing 4-yl/4-yl, 4-yl/3-yl and 3-yl/3-yl substituents represent different combinations of conjugated and cross-conjugated partial structures and cause different spectroscopic properties. In addition, through-space conjugation between the 2- and 2′-position of the thiophenes can be observed which circumvents the charge-separation of through-bond cross-conjugation. The BTE possessing the push–pull chromophore consisting of 3-anisole and 4-pyridinium substituents (24) displays the best extinction coefficients within the series of compounds described here (ϵ=33.8/15.7 L/mol ⋅ cm), while the mesomeric betaine possessing an N-methylpyridinium-4-yl and a 4-phenolate substituent (29) displays considerable bathochromic shifts to λmax=724 nm in its closed form

COMPARATIVE ANALYSIS OF COMPOSITION OF GOLD FOIL FROM ARCHAEOLOGICAL MONUMENTS OF ALTAI, URALS, AND DON REGION: ICP-MS AND XRF DATA

The composition of gold foil from archaeological monuments of Altai, Urals and Don region was studied with ICP-MS and XRF. The foil from the Altai and Uralian monuments is characterized by the higher contents of Pt (54–315 ppm) and Pd (3–13 ppm) in comparison with that from the Don region (3–24 ppm Pt, 0.5–1 ppm Pd). This difference is explained by production of the Altai and Urals foil from PGM-bearing placer gold. The Altai foil, which was made by ancient jewelers from gold extracted from oxidation zones of massive sulfide polymetallic deposits of Rudny Altai, has the higher Zn and Pb contents

EFFLORESCENT SULFATE MINERALS OF THE KARABASH MINING/SMELTING AREA, URAL MOUNTAINS, RU

Karabash is a copper smelting town in the Chelyabinsk district of the Southern Ural mountains of Russia. The town is in close proximity to a large copper deposit and resultant mining activities. Efflorescent minerals from tailings outwash were collected from the mining-impacted landscape. The efflorescent sulfates collected from a variety of sites on tailings outwash adjacent the streams downstream from the Karabash mining zone were dominated by hydrated Fe-Mg-Al sulfates (halotrichite-pickeringite series, melanterite, pentahydrite, magnesiocopiapite, and coquimbite). The efflorescents noted in the tailings outwash site in Karabash appear to be water-soluble salts that crystallized during evaporation of waste-water runoff from the tailings area. The oxidation of the mine wastes acts to liberate sulfur, creating an acidic drainage that leaches both the mine tailings (mobilizing iron and other potentially harmful metals) as well as elements from the rocks around the tailings site. Acid mine drainage, mine and smelter fallout pose a significant environmental concern to the Karabash region

Bis(guanidinium) chloranilate

The asymmetric unit of the title co-crystal, 2CH6N3 +·C6Cl2O4 2−, contains one half of a chloranilate anion and one guanidinium cation, which are connected by strong N—H⋯O hydrogen bonds into a two-dimensional network

THE PROCESS OF MAKING NEW INTERMEDIATE TEMPERATURE PROTON CONDUCTORS THAT BASED ON LITHIUM LANTHANUM ZIRCONATE Li7-xHxLa3Zr2O12 VIA AN ION EXCHANGE

Nowadays the process of searching for the new solid proton electrolytes with high proton conductivity at intermediate temperatures (200–600 oC) is actively developing due to the commercialization of fuel cell technologies. Here we present new materials with high proton conductivity that based on lithium lanthanum zirconate with the general chemical formula Li7-xHxLa3Zr2O12. New materials were made via an ion exchange process between lithium lanthanum zirconate Li7La3Zr2O12 and solutions of acids

Analysis of core samples from the BPXA-DOE-USGS Mount Elbert gas hydrate stratigraphic test well : insights into core disturbance and handling

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine and Petroleum Geology 28 (2011): 381-393, doi:10.1016/j.marpetgeo.2009.10.009.Collecting and preserving undamaged core samples containing gas hydrates from depth is difficult because of the pressure and temperature changes encountered upon retrieval. Hydrate-bearing core samples were collected at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well in February 2007. Coring was performed while using a custom oil-based drilling mud, and the cores were retrieved by a wireline. The samples were characterized and subsampled at the surface under ambient winter arctic conditions. Samples thought to be hydrate bearing were preserved either by immersion in liquid nitrogen (LN), or by storage under methane pressure at ambient arctic conditions, and later depressurized and immersed in LN. Eleven core samples from hydrate-bearing zones were scanned using x-ray computed tomography to examine core structure and homogeneity. Features observed include radial fractures, spalling-type fractures, and reduced density near the periphery. These features were induced during sample collection, handling, and preservation. Isotopic analysis of the methane from hydrate in an initially LN-preserved core and a pressure-preserved core indicate that secondary hydrate formation occurred throughout the pressurized core, whereas none occurred in the LN-preserved core, however no hydrate was found near the periphery of the LN-preserved core. To replicate some aspects of the preservation methods, natural and laboratory-made saturated porous media samples were frozen in a variety of ways, with radial fractures observed in some LN-frozen sands, and needle-like ice crystals forming in slowly frozen clay-rich sediments. Suggestions for hydrate-bearing core preservation are presented.A portion of this work was supported by the Assistant Secretary for Fossil Energy, Office of Natural Gas and Petroleum Technology, through the National Energy Technology Laboratory, under the U.S. DOE Contract No. DE- AC02-05CH11231