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[1] [2] [3] Introduced by Gilbert N. Lewis in his 1916 article The Atom and the Molecule, a Lewis structure can be drawn for any covalently bonded molecule, as well as coordination compounds. [4] Lewis structures extend the concept of the electron dot diagram by adding lines between atoms to represent shared pairs in a chemical bond.
The esters of thiocyanic acid have the general structure R−S−C≡N, where R stands for an organyl group. Isothiocyanic acid, HNCS, is a Lewis acid whose free energy, enthalpy and entropy changes for its 1:1 association with a variety of Lewis bases in carbon tetrachloride solution at 25 °C have been reported.
Thiocyanate [6] is known to be an important part in the biosynthesis of hypothiocyanite by a lactoperoxidase. [7] [8] [9] Thus the complete absence of thiocyanate or reduced thiocyanate [10] in the human body, (e.g., cystic fibrosis) is damaging to the human host defense system.
In a discrete water molecule, there are two hydrogen atoms and one oxygen atom. The simplest case is a pair of water molecules with one hydrogen bond between them, which is called the water dimer and is often used as a model system. When more molecules are present, as is the case with liquid water, more bonds are possible because the oxygen of ...
Single bonds are often seen in diatomic molecules. Examples of this use of single bonds include H 2, F 2, and HCl. Single bonds are also seen in molecules made up of more than two atoms. Examples of this use of single bonds include: Both bonds in H 2 O; All 4 bonds in CH 4; Single bonding even appears in molecules as complex as hydrocarbons ...
In the gas phase, a single water molecule has an oxygen atom surrounded by two hydrogens and two lone pairs, and the H 2 O geometry is simply described as bent without considering the nonbonding lone pairs. [citation needed] However, in liquid water or in ice, the lone pairs form hydrogen bonds with neighboring water molecules. The most common ...
The halides are Lewis acids; for example, ScF 3 dissolves in a solution containing excess fluoride ion to form [ScF 6] 3−. The coordination number 6 is typical for Sc(III). In the larger Y 3+ and La 3+ ions, coordination numbers of 8 and 9 are common. Scandium triflate is sometimes used as a Lewis acid catalyst in organic chemistry.
Although the electronic structure according to valence bond theory can be written as H−N=C=O, the vibrational spectrum has a band at 2268.8 cm −1 in the gas phase, which some say indicates a carbon–nitrogen triple bond. [10] [11] If so, then the canonical form H−N + ≡C−O − is the major resonance structure.