Search Results

You are looking at 1 - 10 of 202 items :

  • "solution equilibria" x
Clear All

1 Nucleosides: structure, nomenclature and solution equilibria 1.1 Nomenclature Nucleosides, the monomeric constituents of nucleic acids, are N-glycosylated deriv- atives of two different categories of heteroaromatic nitrogen bases, namely monocy- clic pyrimidines and bicyclic purines. The pyrimidine bases are cytosine, uracil and thymine, and the purine bases are adenine and guanine. Uracil occurs only in RNA and thymine in DNA, while the other bases are common for both types of nucleic acids. The structures and enumeration of these canonical nucleic acid bases

Main Group Metal Chemistry Vol. 23, No. 9, 2000 SOLUTION EQUILIBRIA AND CHARACTERIZATION OF THE COMPLEX FORMED BETWEEN HIPPURIC ACID AND TIN(II) Predrag Djurdjevic* and Divna Djokic 'Faculty of Science, P.O..box 60, 34000 Kragujevac. Yugoslavia Institute of Nuclear Sciences, Vinca, 11000 Belgrade, Yugoslavia <:preza@ptt.vu> Abstract The complex formation equilibria in tin(II) - hippuric acid (Hhip) solutions were investigated by Potentiometrie glass electrode measurements in 1.0 mol/L NaCl ionic medium at 298 K. Non-linear least-squares analysis of the

ternary solution is written as follows: G T X Xex i ij j ji R= −    == ∑∑ ln Λ 1 3 1 3 (2) where R is the universal gas constant, T is the absolute tempera- ture, and Λ ij stands for the Wilson parameter for the pair of com- ponents i and j. By definition, Λ ii is equal to 1 in Equation 2. By an appropriate differentiation of Equation 2, the activ- ity coefficient of component i (γi) is expressed as follows: Calculations of fluid–ternary solid solution equilibria: An application of the Wilson equation to fluid–(Fe,Mn,Mg)TiO3 equilibria at 600 °C and 1 kbar Y

Zum ambidenten Charakter des Cyanotrihydroborat-Liganden in Uran(IV)-Organylen On the Ambident Nature of the Cyanotrihydroborate Ligand in Organouranium(IV) Complexes R. Dieter Fischer+ und Kenan Yünlü Institut für Anorganische und Angewandte Chemie der Universität Hamburg, Martin - Luther - King - Platz 6, D-2000 Hamburg 13 Herrn Prof. Dr. Dr. h. c. mult. E. O. Fischer zum 65. Geburtstag gewidmet Z. Naturforsch. 88b, 1369-1374 (1983); eingegangen am 6. Juli 1983 Uranium Organyls, Cyanotrihydroborate Ligand, NMR of Paramagnetic Species, Solution

Phenomena related to the solubility of solids, liquids, and gases with one another are of interest to scientists and technologists in an array of disciplines. The diversity of backgrounds of individuals concerned with solubility creates a potential for confusion and miscommunication and heightens the need for an authoritative glossary of terms related to solubility. This glossary defines 166 terms used to describe solubility and related phenomena. The definitions are consistent with one another and with recommendations of the International Union of Pure and Applied Chemistry for terminology and nomenclature.

Abstract

Numerical simulations were carried out for determining the chemical reactions relevant for the sequestration of CO2 in basaltic rock formations. The mineralogy of natural geological systems consists of silicate minerals such as the phyllosilicates and zeolites that form complex solid solutions. Using the GEMS code package based on Gibbs energy minimization, combined with the new MINES database, we can now simulate the solubility of these multicomponent and multisite mineral solid solutions in basaltic rocks. This study explores the varying effects of CO2 partial pressures, basaltic glass dissolution kinetics and reaction time on the complex chemistry of the overall CO2-water-basalt reaction path. The simulations indicate four reaction progress stages with the competing reactions between smectites (di- and trioctahedral) and Ca-Fe-Mg-carbonates controlling the amount of CO2 mineralized. A better understanding of these key mineral-fluid reactions and improvement of their thermodynamic models is critical for making more acurate predictive calculations. This comprises the basis for extending the simulations to reactive transport models, and for the assessment of the feasibility of long-term CO2 storage in basaltic rock formations.

The IUPAC-NIST Solubility Data Series (SDS) is an ongoing project that provides comprehensive reviews of published data for solubilities of gases, liquids, and solids in liquids or solids. Data are compiled in a uniform format, evaluated, and, where data from independent sources agree sufficiently, recommended values are proposed. This paper is a guide to the SDS and is intended for the benefit of both those who use the SDS as a source of critically evaluated solubility data and who prepare compilations and evaluations for future volumes. A major portion of this paper presents terminology and nomenclature currently recommended by IUPAC and other international bodies and relates these to obsolete forms that appear in the older solubility literature. In addition, this paper presents a detailed guide to the criteria and procedures used in data compilation, evaluation, and presentation and considers special features of solubility in gas + liquid, liquid + liquid, and solid + liquid systems. In the past, much of this information was included in introductory sections of individual volumes of the SDS. However, to eliminate repetitive publication, this information has been collected, updated, and expanded for separate publication here.

fluxional on the NMR time scale and best described as Cd[(a-H)2BH2]2- rcTHF as indicated by IR data. Reactions of LiBH4 with Cd(BH4)2 in THF yield the monoanion [Cd(BH4)3]_ exclusively, while a dilithium salt Li2[Cd(BH4)4] • 4 diglyme precipitates from diglyme solutions. Equilibria involving ICd(BH4), Cdl2, Cdl3~, [Cd(BH4)3]- and/or [ICd(BH4)2]~ result from Cd(BH4)2 and Lil in THF or diglyme. The solvent as well as the cation of the iodide (Cd2+ or Li+) influence the equilibria. This can be explained in terms of the different polarity and chelating ability of the

controlled thermodynamic variable (e.g. the oxygen partial pressure P ( 0 2 ) for the defect equilibria in a simple oxide, or a total concentration for the ionic equilibria in solution) on a chemically relevant compositional variable (such as the electron concentration n for defect equilibria, or [ H 3 0 + ] or a free ligand concentration for solution equilibria). This functional dependency can be safely inverted. The concentration of all species and the externally controlled thermodynamic variable can be calculated as a function of the chemically relevant