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In organic chemistry, neighbouring group participation (NGP, also known as anchimeric assistance) has been defined by the International Union of Pure and Applied Chemistry (IUPAC) as the interaction of a reaction centre with a lone pair of electrons in an atom or the electrons present in a sigma or pi bond contained within the parent molecule but not conjugated with the reaction centre.
CALPHAD stands for Computer Coupling of Phase Diagrams and Thermochemistry, a methodology introduced in 1970 by Larry Kaufman, originally known as CALculation of PHAse Diagrams. [1] [2] [3] An equilibrium phase diagram is usually a diagram with axes for temperature and composition of a chemical system. It shows the regions where substances or ...
The side of the diagram between calcite and sillimanite has a point added for anorthite (calcium feldspar), corresponding to an equal mixture (by mole percentage) of the two components. This forms pure anorthite. Likewise, points are added for clinopyroxene and garnet and the diagram is divided into subtriangles, as depicted in the accompanying ...
Crystal structure of calcite. Calcium carbonate is a chemical compound with the chemical formula Ca CO 3.It is a common substance found in rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls.
Non-covalent interactions can be classified into different categories, such as electrostatic, π-effects, van der Waals forces, and hydrophobic effects. [3] [2] Non-covalent interactions [4] are critical in maintaining the three-dimensional structure of large molecules, such as proteins and nucleic acids.
Pourbaix diagram of iron. [1] The Y axis corresponds to voltage potential. In electrochemistry, and more generally in solution chemistry, a Pourbaix diagram, also known as a potential/pH diagram, E H –pH diagram or a pE/pH diagram, is a plot of possible thermodynamically stable phases (i.e., at chemical equilibrium) of an aqueous electrochemical system.
The species distribution diagram shows that the concentrations of the two ions are maximum at pH 5.5 and 10. % species formation calculated with the program HySS for a 10 millimolar solution of citric acid. pK a1 = 3.13, pK a2 = 4.76, pK a3 = 6.40.
The reaction between hydrochloric acid and calcium carbonate (limestone or chalk) is shown below: CaCO 3 + 2 HCl → CaCl 2 + H 2 CO 3. The carbonic acid (H 2 CO 3) then decomposes to water and CO 2: H 2 CO 3 → CO 2 + H 2 O. Such reactions are accompanied by foaming or bubbling, or both, as the gas is released.