Search results
Results From The WOW.Com Content Network
In the same year that Brønsted and Lowry published their theory, G. N. Lewis created an alternative theory of acid–base reactions. The Lewis theory is based on electronic structure. A Lewis base is a compound that can give an electron pair to a Lewis acid, a compound that can accept an electron pair.
Lewis structure of a water molecule. Lewis structures – also called Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDs) – are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.
Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the formula HCN and structural formula H−C≡N.It is a highly toxic and flammable liquid that boils slightly above room temperature, at 25.6 °C (78.1 °F).
In chemistry, an acid–base reaction is a chemical reaction that occurs between an acid and a base.It can be used to determine pH via titration.Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
The most common Lewis bases are anions. The strength of Lewis basicity correlates with the pK a of the parent acid: acids with high pK a 's give good Lewis bases. As usual, a weaker acid has a stronger conjugate base. Examples of Lewis bases based on the general definition of electron pair donor include: simple anions, such as H − and F −
Skeletal structural formula of Vitamin B 12.Many organic molecules are too complicated to be specified by a molecular formula.. The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are possibly arranged in the real three-dimensional space.
In situ formation of HCN can be sourced using precursors such as acetone cyanohydrin. Alternatively, cyano-silyl derivatives such as TMS-CN allows for both the cyanation and protection in one step without the need for HCN. [6] Similar procedures relying on ester, phosphate and carbonate formation have been reported. [7] [8] [9]
The reaction can be simplified by replacing the HCN/AlCl 3 combination with zinc cyanide. [4] Although it is also highly toxic, Zn(CN) 2 is a solid, making it safer to work with than gaseous HCN. [5] The Zn(CN) 2 reacts with the HCl to form the key HCN reactant and Zn(Cl) 2 that serves as the Lewis-acid catalyst in-situ.