نتایج جستجو برای: sulfate so4
تعداد نتایج: 60811 فیلتر نتایج به سال:
Introduction: The Mars Exploration Rover (MER) missions have stimulated considerable thinking about the surficial geochemical evolution of Mars [1-4]. Among the major MER findings is the presence of the mineral, jarosite (a ferric sulfate salt), which suggests formation from an acid-sulfate brine. The objectives of this work were to (1) add ferric iron chemistry to an existing ferrous iron mode...
Introduction: There is a growing interest in the study of sulfate minerals on the surface of Mars, supported by the discovery of jarosite at Meridiani Planum [1-3]. There is also the possibility of finding hydrous sulfate minerals in the permafrost, located at the polar regions. Sulfate minerals often precipitate in a variety of hydration states in the presence of liquid water. The spectra of s...
Arsenic-bearing synthetic jarosite [KFe3(SO4)2(OH)6] was characterized to elucidate the form of the arsenic. The XANES spectra indicate that the As occurs exclusively as As5+, nominally as AsO4, consistent with the valence state of the arsenic in the reagents used for the syntheses. X-ray-diffraction analyses show that at least 9.9 wt.% AsO4 can be structurally incorporated in the jarosite. Cel...
This paper presents measurements of daily sampling of fine particulate matter (PM2.5) and its major chemical components at three urban and one rural locations in North Carolina during 2002. At both urban and rural sites, the major insoluble component of PM2.5 is organic matter, and the major soluble components are sulfate (SO4(2-)), ammonium (NH4(+)), and nitrate (NO3(-)). NH4(+) is neutralized...
Mutant strains of the yeast Saccharomyces cerevisiae which lack functional Cu,Zn superoxide dismutase (SOD-1) do not grow aerobically unless supplemented with methionine. The molecular basis of this O2-dependent auxotrophy in one of the mutants, Dscd1-1C, has been investigated. Sulfate supported anaerobic but not aerobic mutant growth. On the other hand, cysteine and homocysteine supported aero...
Calcined clay blended cements play a major role in cement industry's strategy to reduce CO2 emissions. During their hydration, an accelerated aluminate reaction is often observed affect the sulfate balance. The objective of this study was provide insights into influence different calcined clays on hydration cubic tricalcium (C3A). A cementitious model system consisting C3A, quartz powder, calci...
Oxygen isotopes in marine sulfate (delta18O(SO4)) measured in marine barite show variability over the past 10 million years, including a 5 per mil decrease during the Plio-Pleistocene, with near-constant values during the Miocene that are slightly enriched over the modern ocean. A numerical model suggests that sea level fluctuations during Plio-Pleistocene glacial cycles affected the sulfur cyc...
In the title compound, [Zn(SO4)(C12H8N2)2]·C3H8O2, the Zn(II) ion is in a distorted square-pyramidal coordination environment composed of four N atoms from two chelating 1,10-phenanthroline ligands and one O atom from a monodentate sulfate ligand. The Zn(II) ion lies on a twofold rotation axis. The sulfate ligand and propane-1,2-diol mol-ecules are disordered across the twofold rotation axis. T...
The crystal structure of the title salt {systematic name: [1,3-phenyl-enebis(methyl-ene)]bis-(aza-nium) sulfate}, C8H14N2 (2+)·SO4 (2-), consists of infinite (100) sheets of alternating organic and inorganic entities The m-xylylenediaminium cations are linked to the sulfate anions by N-H⋯O and asymmetric bifurcated N-H⋯(O,O) hydrogen bonds, generating a three-dimensional network. A weak C-H⋯O i...
A new organic-inorganic hybrid compound, penta-morpholinium hexa-hydrogen hexa-molybdoferrate(III) sulfate 3.5-hydrate, (C4H10NO)5[Fe(III)(OH)6Mo6O18](SO4)·3.5H2O, was obtained from an aqueous solution. The polyoxidomolybdate (POM) anion is of the Anderson β-type with a central Fe(III) ion. Three of five crystallographically independent morpholinium cations are disordered over two sets of sites...
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